* [PATCH V9] Add support for BTRFS raid5/6 to GRUB @ 2018-10-11 18:50 Goffredo Baroncelli 2018-10-11 18:50 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli ` (8 more replies) 0 siblings, 9 replies; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-11 18:50 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs Hi All, the aim of this patches set is to provide support for a BTRFS raid5/6 filesystem in GRUB. The first patch, implements the basic support for raid5/6. I.e this works when all the disks are present. The next 5 patches, are preparatory ones. The 7th patch implements the raid5 recovery for btrfs (i.e. handling the disappearing of 1 disk). The 8th patch makes the code for handling the raid6 recovery more generic. The last one implements the raid6 recovery for btrfs (i.e. handling the disappearing up to two disks). I tested the code in grub-emu, and it works both with all the disks, and with some disks missing. I checked the crc32 calculated from grub and from linux and these matched. Finally I checked if the support for md raid6 still works properly, and it does (with all drives and with up to 2 drives missing) Comments are welcome. Changelog v1: initial support for btrfs raid5/6. No recovery allowed v2: full support for btrfs raid5/6. Recovery allowed v3: some minor cleanup suggested by Daniel Kiper; reusing the original raid6 recovery code of grub v4: Several spell fix; better description of the RAID layout in btrfs, and the variables which describes the stripe positioning; split the patch #5 in two (#5 and #6) v5: Several spell fix; improved code comment in patch #1, small clean up in the code v6: Small cleanup; improved the wording in the RAID6 layout description; in the function raid6_recover_read_buffer() avoid a unnecessary memcpy in case of invalid data; v7: - patch 2,3,5,6,8 received an Review-by Daniel, and were unchanged from the last time (only minor cleanup in the commit description requested by Daniel) - patch 7 received some small update rearranging a for(), and some bracket around if() - patch 4, received an update message which explains better why NULL is stored in data->devices_attached[] - patch 9, received a blank line to separate better a code line from a previous comment. A description of 'parities_pos' was added - patch 1, received a major update about the variable meaning description in the comment. However I suspect that we need some further review to reach a fully agreement about this text. NB: the update are relate only to comments v8: - patch 2,5,6,8 received an Review-by Daniel, and were unchanged from the last time (only minor cleanup in the commit description requested by Daniel) - patch 1 received some adjustement to the variables description due to the different terminology between BTRFS and other RAID implementatio. Added a description for the "nparities" variable. - patch 3 removed some unnecessary curly brackets (change request by Daniel) - patch 4 received an improved commit description about why and how the function find_device() is changed - patch 7 received an update which transforms a i = 0; while(i..) i++; in for( i = 0..... ; i++); - patch 9 received an update to the comment v9: - patch 1: update comments - patch 4: update commit messages - patch 7: added a comment about accessing an array of structs after another structs; changed if(err == GRUB_ERR_NONE) in if(!err) changed if(err != GRUB_ERR_NONE) in if(err) BR G.Baroncelli -- gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-10-11 18:50 [PATCH V9] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli @ 2018-10-11 18:50 ` Goffredo Baroncelli 2018-10-17 13:46 ` Daniel Kiper 2018-10-11 18:50 ` [PATCH 2/9] btrfs: Add helper to check the btrfs header Goffredo Baroncelli ` (7 subsequent siblings) 8 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-11 18:50 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/fs/btrfs.c | 73 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index be195448d..933a57d3b 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item #define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10 #define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20 #define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40 +#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80 +#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100 grub_uint8_t dummy2[0xc]; grub_uint16_t nstripes; grub_uint16_t nsubstripes; @@ -764,6 +766,77 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, stripe_offset = low + chunk_stripe_length * high; csize = chunk_stripe_length - low; + break; + } + case GRUB_BTRFS_CHUNK_TYPE_RAID5: + case GRUB_BTRFS_CHUNK_TYPE_RAID6: + { + grub_uint64_t nparities, stripe_nr, high, low; + + redundancy = 1; /* no redundancy for now */ + + if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5) + { + grub_dprintf ("btrfs", "RAID5\n"); + nparities = 1; + } + else + { + grub_dprintf ("btrfs", "RAID6\n"); + nparities = 2; + } + + /* + * RAID 6 layout consists of several stripes spread over + * the disks, e.g.: + * + * Disk_0 Disk_1 Disk_2 Disk_3 + * A0 B0 P0 Q0 + * Q1 A1 B1 P1 + * P2 Q2 A2 B2 + * + * Note: placement of the parities depend on row number. + * + * Pay attention that the btrfs terminology may differ from + * terminology used in other RAID implementations, e.g. LVM, + * dm or md. The main difference is that btrfs calls contiguous + * block of data on a given disk, e.g. A0, stripe instead of chunk. + * + * The variables listed below have following meaning: + * - stripe_nr is the stripe number excluding the parities + * (A0 = 0, B0 = 1, A1 = 2, B1 = 3, etc.), + * - high is the row number (0 for A0...Q0, 1 for Q1...P1, etc.), + * - stripen is the disk number in a row (0 for A0, Q1, P2, + * 1 for B0, A1, Q2, etc.), + * - off is the logical address to read, + * - chunk_stripe_length is the size of a stripe (typically 64 KiB), + * - nstripes is the number of disks in a row, + * - low is the offset of the data inside a stripe, + * - stripe_offset is the data offset in an array, + * - csize is the "potential" data to read; it will be reduced + * to size if the latter is smaller, + * - nparities is the number of parities (1 for RAID 5, 2 for + * RAID 6); used only in RAID 5/6 code. + */ + stripe_nr = grub_divmod64 (off, chunk_stripe_length, &low); + + /* + * stripen is computed without the parities + * (0 for A0, A1, A2, 1 for B0, B1, B2, etc.). + */ + high = grub_divmod64 (stripe_nr, nstripes - nparities, &stripen); + + /* + * The stripes are spread over the disks. Every each row their + * positions are shifted by 1 place. So, the real disks number + * change. Hence, we have to take current row number modulo + * nstripes into account (0 for A0, 1 for A1, 2 for A2, etc.). + */ + grub_divmod64 (high + stripen, nstripes, &stripen); + + stripe_offset = low + chunk_stripe_length * high; + csize = chunk_stripe_length - low; + break; } default: -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* Re: [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-10-11 18:50 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli @ 2018-10-17 13:46 ` Daniel Kiper 0 siblings, 0 replies; 23+ messages in thread From: Daniel Kiper @ 2018-10-17 13:46 UTC (permalink / raw) To: Goffredo Baroncelli Cc: grub-devel, Daniel Kiper, linux-btrfs, Goffredo Baroncelli On Thu, Oct 11, 2018 at 08:50:55PM +0200, Goffredo Baroncelli wrote: > From: Goffredo Baroncelli <kreijack@inwind.it> > > Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> > Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com> One nit pick below... Otherwise you can add Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> > --- > grub-core/fs/btrfs.c | 73 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 73 insertions(+) > > diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c > index be195448d..933a57d3b 100644 > --- a/grub-core/fs/btrfs.c > +++ b/grub-core/fs/btrfs.c > @@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item > #define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10 > #define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20 > #define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40 > +#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80 > +#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100 > grub_uint8_t dummy2[0xc]; > grub_uint16_t nstripes; > grub_uint16_t nsubstripes; > @@ -764,6 +766,77 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, > stripe_offset = low + chunk_stripe_length > * high; > csize = chunk_stripe_length - low; > + break; > + } > + case GRUB_BTRFS_CHUNK_TYPE_RAID5: > + case GRUB_BTRFS_CHUNK_TYPE_RAID6: > + { > + grub_uint64_t nparities, stripe_nr, high, low; > + > + redundancy = 1; /* no redundancy for now */ > + > + if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5) > + { > + grub_dprintf ("btrfs", "RAID5\n"); > + nparities = 1; > + } > + else > + { > + grub_dprintf ("btrfs", "RAID6\n"); > + nparities = 2; > + } > + > + /* > + * RAID 6 layout consists of several stripes spread over > + * the disks, e.g.: > + * > + * Disk_0 Disk_1 Disk_2 Disk_3 > + * A0 B0 P0 Q0 > + * Q1 A1 B1 P1 > + * P2 Q2 A2 B2 > + * > + * Note: placement of the parities depend on row number. > + * > + * Pay attention that the btrfs terminology may differ from > + * terminology used in other RAID implementations, e.g. LVM, > + * dm or md. The main difference is that btrfs calls contiguous > + * block of data on a given disk, e.g. A0, stripe instead of chunk. > + * > + * The variables listed below have following meaning: > + * - stripe_nr is the stripe number excluding the parities > + * (A0 = 0, B0 = 1, A1 = 2, B1 = 3, etc.), > + * - high is the row number (0 for A0...Q0, 1 for Q1...P1, etc.), > + * - stripen is the disk number in a row (0 for A0, Q1, P2, > + * 1 for B0, A1, Q2, etc.), > + * - off is the logical address to read, > + * - chunk_stripe_length is the size of a stripe (typically 64 KiB), > + * - nstripes is the number of disks in a row, > + * - low is the offset of the data inside a stripe, > + * - stripe_offset is the data offset in an array, > + * - csize is the "potential" data to read; it will be reduced > + * to size if the latter is smaller, > + * - nparities is the number of parities (1 for RAID 5, 2 for > + * RAID 6); used only in RAID 5/6 code. > + */ > + stripe_nr = grub_divmod64 (off, chunk_stripe_length, &low); > + > + /* > + * stripen is computed without the parities > + * (0 for A0, A1, A2, 1 for B0, B1, B2, etc.). > + */ > + high = grub_divmod64 (stripe_nr, nstripes - nparities, &stripen); > + > + /* > + * The stripes are spread over the disks. Every each row their > + * positions are shifted by 1 place. So, the real disks number > + * change. Hence, we have to take current row number modulo > + * nstripes into account (0 for A0, 1 for A1, 2 for A2, etc.). s/current row number modulo nstripes into account/into account current row number modulo nstripes/ Daniel ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 2/9] btrfs: Add helper to check the btrfs header. 2018-10-11 18:50 [PATCH V9] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli 2018-10-11 18:50 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli @ 2018-10-11 18:50 ` Goffredo Baroncelli 2018-10-11 18:50 ` [PATCH 3/9] btrfs: Move the error logging from find_device() to its caller Goffredo Baroncelli ` (6 subsequent siblings) 8 siblings, 0 replies; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-11 18:50 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> This helper is used in a few places to help the debugging. As conservative approach the error is only logged. This does not impact the error handling. Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/fs/btrfs.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index 933a57d3b..c9f0c4193 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -77,7 +77,8 @@ struct btrfs_header { grub_btrfs_checksum_t checksum; grub_btrfs_uuid_t uuid; - grub_uint8_t dummy[0x30]; + grub_uint64_t bytenr; + grub_uint8_t dummy[0x28]; grub_uint32_t nitems; grub_uint8_t level; } GRUB_PACKED; @@ -286,6 +287,25 @@ free_iterator (struct grub_btrfs_leaf_descriptor *desc) grub_free (desc->data); } +static grub_err_t +check_btrfs_header (struct grub_btrfs_data *data, struct btrfs_header *header, + grub_disk_addr_t addr) +{ + if (grub_le_to_cpu64 (header->bytenr) != addr) + { + grub_dprintf ("btrfs", "btrfs_header.bytenr is not equal node addr\n"); + return grub_error (GRUB_ERR_BAD_FS, + "header bytenr is not equal node addr"); + } + if (grub_memcmp (data->sblock.uuid, header->uuid, sizeof(grub_btrfs_uuid_t))) + { + grub_dprintf ("btrfs", "btrfs_header.uuid doesn't match sblock uuid\n"); + return grub_error (GRUB_ERR_BAD_FS, + "header uuid doesn't match sblock uuid"); + } + return GRUB_ERR_NONE; +} + static grub_err_t save_ref (struct grub_btrfs_leaf_descriptor *desc, grub_disk_addr_t addr, unsigned i, unsigned m, int l) @@ -341,6 +361,7 @@ next (struct grub_btrfs_data *data, err = grub_btrfs_read_logical (data, grub_le_to_cpu64 (node.addr), &head, sizeof (head), 0); + check_btrfs_header (data, &head, grub_le_to_cpu64 (node.addr)); if (err) return -err; @@ -402,6 +423,7 @@ lower_bound (struct grub_btrfs_data *data, /* FIXME: preread few nodes into buffer. */ err = grub_btrfs_read_logical (data, addr, &head, sizeof (head), recursion_depth + 1); + check_btrfs_header (data, &head, addr); if (err) return err; addr += sizeof (head); -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH 3/9] btrfs: Move the error logging from find_device() to its caller. 2018-10-11 18:50 [PATCH V9] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli 2018-10-11 18:50 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli 2018-10-11 18:50 ` [PATCH 2/9] btrfs: Add helper to check the btrfs header Goffredo Baroncelli @ 2018-10-11 18:50 ` Goffredo Baroncelli 2018-10-11 18:50 ` [PATCH 4/9] btrfs: Avoid a rescan for a device which was already not found Goffredo Baroncelli ` (5 subsequent siblings) 8 siblings, 0 replies; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-11 18:50 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> The caller knows better if this error is fatal or not, i.e. another disk is available or not. This is a preparatory patch. Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/fs/btrfs.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index c9f0c4193..2a87eb103 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -603,12 +603,7 @@ find_device (struct grub_btrfs_data *data, grub_uint64_t id, int do_rescan) if (do_rescan) grub_device_iterate (find_device_iter, &ctx); if (!ctx.dev_found) - { - grub_error (GRUB_ERR_BAD_FS, - N_("couldn't find a necessary member device " - "of multi-device filesystem")); - return NULL; - } + return NULL; data->n_devices_attached++; if (data->n_devices_attached > data->n_devices_allocated) { @@ -905,6 +900,9 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, dev = find_device (data, stripe->device_id, j); if (!dev) { + grub_dprintf ("btrfs", + "couldn't find a necessary member device " + "of multi-device filesystem\n"); err = grub_errno; grub_errno = GRUB_ERR_NONE; continue; -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH 4/9] btrfs: Avoid a rescan for a device which was already not found. 2018-10-11 18:50 [PATCH V9] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli ` (2 preceding siblings ...) 2018-10-11 18:50 ` [PATCH 3/9] btrfs: Move the error logging from find_device() to its caller Goffredo Baroncelli @ 2018-10-11 18:50 ` Goffredo Baroncelli 2018-10-17 13:51 ` Daniel Kiper 2018-10-11 18:50 ` [PATCH 5/9] btrfs: Move logging code in grub_btrfs_read_logical() Goffredo Baroncelli ` (4 subsequent siblings) 8 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-11 18:50 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> Currently read from missing device triggers rescan. However, it is never recorded that the device is missing. So, each read of a missing device triggers rescan again and again. This behavior causes a lot of unneeded rescans leading to huge slowdowns. This patch fixes above mentioned issue. Information about missing devices is stored in the data->devices_attached[] array as NULL value in dev member. Rescan is triggered only if no information is found for a given device. This means that only first time read triggers rescan. The patch drops premature return. This way data->devices_attached[] is filled even when a given device is missing. Signed-off-by: Goffredo Baroncelli <kreikack@inwind.it> --- grub-core/fs/btrfs.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index 2a87eb103..b2be80c33 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -588,7 +588,7 @@ find_device_iter (const char *name, void *data) } static grub_device_t -find_device (struct grub_btrfs_data *data, grub_uint64_t id, int do_rescan) +find_device (struct grub_btrfs_data *data, grub_uint64_t id) { struct find_device_ctx ctx = { .data = data, @@ -600,10 +600,9 @@ find_device (struct grub_btrfs_data *data, grub_uint64_t id, int do_rescan) for (i = 0; i < data->n_devices_attached; i++) if (id == data->devices_attached[i].id) return data->devices_attached[i].dev; - if (do_rescan) - grub_device_iterate (find_device_iter, &ctx); - if (!ctx.dev_found) - return NULL; + + grub_device_iterate (find_device_iter, &ctx); + data->n_devices_attached++; if (data->n_devices_attached > data->n_devices_allocated) { @@ -615,7 +614,8 @@ find_device (struct grub_btrfs_data *data, grub_uint64_t id, int do_rescan) * sizeof (data->devices_attached[0])); if (!data->devices_attached) { - grub_device_close (ctx.dev_found); + if (ctx.dev_found) + grub_device_close (ctx.dev_found); data->devices_attached = tmp; return NULL; } @@ -897,7 +897,7 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, " for laddr 0x%" PRIxGRUB_UINT64_T "\n", paddr, addr); - dev = find_device (data, stripe->device_id, j); + dev = find_device (data, stripe->device_id); if (!dev) { grub_dprintf ("btrfs", @@ -974,7 +974,8 @@ grub_btrfs_unmount (struct grub_btrfs_data *data) unsigned i; /* The device 0 is closed one layer upper. */ for (i = 1; i < data->n_devices_attached; i++) - grub_device_close (data->devices_attached[i].dev); + if (data->devices_attached[i].dev) + grub_device_close (data->devices_attached[i].dev); grub_free (data->devices_attached); grub_free (data->extent); grub_free (data); -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* Re: [PATCH 4/9] btrfs: Avoid a rescan for a device which was already not found. 2018-10-11 18:50 ` [PATCH 4/9] btrfs: Avoid a rescan for a device which was already not found Goffredo Baroncelli @ 2018-10-17 13:51 ` Daniel Kiper 0 siblings, 0 replies; 23+ messages in thread From: Daniel Kiper @ 2018-10-17 13:51 UTC (permalink / raw) To: Goffredo Baroncelli Cc: grub-devel, Daniel Kiper, linux-btrfs, Goffredo Baroncelli On Thu, Oct 11, 2018 at 08:50:58PM +0200, Goffredo Baroncelli wrote: > From: Goffredo Baroncelli <kreijack@inwind.it> > > Currently read from missing device triggers rescan. However, it is never > recorded that the device is missing. So, each read of a missing device > triggers rescan again and again. This behavior causes a lot of unneeded > rescans leading to huge slowdowns. > > This patch fixes above mentioned issue. Information about missing devices > is stored in the data->devices_attached[] array as NULL value in dev > member. Rescan is triggered only if no information is found for a given > device. This means that only first time read triggers rescan. > > The patch drops premature return. This way data->devices_attached[] is > filled even when a given device is missing. > > Signed-off-by: Goffredo Baroncelli <kreikack@inwind.it> I changed commit message, so, you should add Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com> I simply forgot to tell you about that. Sorry. And below you can add Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> Daniel ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 5/9] btrfs: Move logging code in grub_btrfs_read_logical() 2018-10-11 18:50 [PATCH V9] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli ` (3 preceding siblings ...) 2018-10-11 18:50 ` [PATCH 4/9] btrfs: Avoid a rescan for a device which was already not found Goffredo Baroncelli @ 2018-10-11 18:50 ` Goffredo Baroncelli 2018-10-11 18:51 ` [PATCH 6/9] btrfs: Refactor the code that read from disk Goffredo Baroncelli ` (3 subsequent siblings) 8 siblings, 0 replies; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-11 18:50 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> A portion of the logging code is moved outside of internal for(;;). The part that is left inside is the one which depends on the internal for(;;) index. This is a preparatory patch. The next one will refactor the code inside the for(;;) into an another function. Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/fs/btrfs.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index b2be80c33..a82211ccc 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -870,6 +870,18 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, for (j = 0; j < 2; j++) { + grub_dprintf ("btrfs", "chunk 0x%" PRIxGRUB_UINT64_T + "+0x%" PRIxGRUB_UINT64_T + " (%d stripes (%d substripes) of %" + PRIxGRUB_UINT64_T ")\n", + grub_le_to_cpu64 (key->offset), + grub_le_to_cpu64 (chunk->size), + grub_le_to_cpu16 (chunk->nstripes), + grub_le_to_cpu16 (chunk->nsubstripes), + grub_le_to_cpu64 (chunk->stripe_length)); + grub_dprintf ("btrfs", "reading laddr 0x%" PRIxGRUB_UINT64_T "\n", + addr); + for (i = 0; i < redundancy; i++) { struct grub_btrfs_chunk_stripe *stripe; @@ -882,20 +894,11 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, paddr = grub_le_to_cpu64 (stripe->offset) + stripe_offset; - grub_dprintf ("btrfs", "chunk 0x%" PRIxGRUB_UINT64_T - "+0x%" PRIxGRUB_UINT64_T - " (%d stripes (%d substripes) of %" - PRIxGRUB_UINT64_T ") stripe %" PRIxGRUB_UINT64_T + grub_dprintf ("btrfs", "stripe %" PRIxGRUB_UINT64_T " maps to 0x%" PRIxGRUB_UINT64_T "\n", - grub_le_to_cpu64 (key->offset), - grub_le_to_cpu64 (chunk->size), - grub_le_to_cpu16 (chunk->nstripes), - grub_le_to_cpu16 (chunk->nsubstripes), - grub_le_to_cpu64 (chunk->stripe_length), stripen, stripe->offset); grub_dprintf ("btrfs", "reading paddr 0x%" PRIxGRUB_UINT64_T - " for laddr 0x%" PRIxGRUB_UINT64_T "\n", paddr, - addr); + "\n", paddr); dev = find_device (data, stripe->device_id); if (!dev) -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH 6/9] btrfs: Refactor the code that read from disk 2018-10-11 18:50 [PATCH V9] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli ` (4 preceding siblings ...) 2018-10-11 18:50 ` [PATCH 5/9] btrfs: Move logging code in grub_btrfs_read_logical() Goffredo Baroncelli @ 2018-10-11 18:51 ` Goffredo Baroncelli 2018-10-11 18:51 ` [PATCH 7/9] btrfs: Add support for recovery for a RAID 5 btrfs profiles Goffredo Baroncelli ` (2 subsequent siblings) 8 siblings, 0 replies; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-11 18:51 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> Move the code in charge to read the data from disk into a separate function. This helps to separate the error handling logic (which depends on the different raid profiles) from the read from disk logic. Refactoring this code increases the general readability too. This is a preparatory patch, to help the adding of the RAID 5/6 recovery code. Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/fs/btrfs.c | 75 ++++++++++++++++++++++++++------------------ 1 file changed, 44 insertions(+), 31 deletions(-) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index a82211ccc..899dc32b7 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -625,6 +625,46 @@ find_device (struct grub_btrfs_data *data, grub_uint64_t id) return ctx.dev_found; } +static grub_err_t +btrfs_read_from_chunk (struct grub_btrfs_data *data, + struct grub_btrfs_chunk_item *chunk, + grub_uint64_t stripen, grub_uint64_t stripe_offset, + int redundancy, grub_uint64_t csize, + void *buf) +{ + struct grub_btrfs_chunk_stripe *stripe; + grub_disk_addr_t paddr; + grub_device_t dev; + grub_err_t err; + + stripe = (struct grub_btrfs_chunk_stripe *) (chunk + 1); + /* Right now the redundancy handling is easy. + With RAID5-like it will be more difficult. */ + stripe += stripen + redundancy; + + paddr = grub_le_to_cpu64 (stripe->offset) + stripe_offset; + + grub_dprintf ("btrfs", "stripe %" PRIxGRUB_UINT64_T + " maps to 0x%" PRIxGRUB_UINT64_T + ". Reading paddr 0x%" PRIxGRUB_UINT64_T "\n", + stripen, stripe->offset, paddr); + + dev = find_device (data, stripe->device_id); + if (!dev) + { + grub_dprintf ("btrfs", + "couldn't find a necessary member device " + "of multi-device filesystem\n"); + grub_errno = GRUB_ERR_NONE; + return GRUB_ERR_READ_ERROR; + } + + err = grub_disk_read (dev->disk, paddr >> GRUB_DISK_SECTOR_BITS, + paddr & (GRUB_DISK_SECTOR_SIZE - 1), + csize, buf); + return err; +} + static grub_err_t grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, void *buf, grub_size_t size, int recursion_depth) @@ -638,7 +678,6 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, grub_err_t err = 0; struct grub_btrfs_key key_out; int challoc = 0; - grub_device_t dev; struct grub_btrfs_key key_in; grub_size_t chsize; grub_disk_addr_t chaddr; @@ -884,36 +923,10 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, for (i = 0; i < redundancy; i++) { - struct grub_btrfs_chunk_stripe *stripe; - grub_disk_addr_t paddr; - - stripe = (struct grub_btrfs_chunk_stripe *) (chunk + 1); - /* Right now the redundancy handling is easy. - With RAID5-like it will be more difficult. */ - stripe += stripen + i; - - paddr = grub_le_to_cpu64 (stripe->offset) + stripe_offset; - - grub_dprintf ("btrfs", "stripe %" PRIxGRUB_UINT64_T - " maps to 0x%" PRIxGRUB_UINT64_T "\n", - stripen, stripe->offset); - grub_dprintf ("btrfs", "reading paddr 0x%" PRIxGRUB_UINT64_T - "\n", paddr); - - dev = find_device (data, stripe->device_id); - if (!dev) - { - grub_dprintf ("btrfs", - "couldn't find a necessary member device " - "of multi-device filesystem\n"); - err = grub_errno; - grub_errno = GRUB_ERR_NONE; - continue; - } - - err = grub_disk_read (dev->disk, paddr >> GRUB_DISK_SECTOR_BITS, - paddr & (GRUB_DISK_SECTOR_SIZE - 1), - csize, buf); + err = btrfs_read_from_chunk (data, chunk, stripen, + stripe_offset, + i, /* redundancy */ + csize, buf); if (!err) break; grub_errno = GRUB_ERR_NONE; -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH 7/9] btrfs: Add support for recovery for a RAID 5 btrfs profiles. 2018-10-11 18:50 [PATCH V9] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli ` (5 preceding siblings ...) 2018-10-11 18:51 ` [PATCH 6/9] btrfs: Refactor the code that read from disk Goffredo Baroncelli @ 2018-10-11 18:51 ` Goffredo Baroncelli 2018-10-17 14:14 ` Daniel Kiper 2018-10-11 18:51 ` [PATCH 8/9] btrfs: Make more generic the code for RAID 6 rebuilding Goffredo Baroncelli 2018-10-11 18:51 ` [PATCH 9/9] btrfs: Add RAID 6 recovery for a btrfs filesystem Goffredo Baroncelli 8 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-11 18:51 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> Add support for recovery for a RAID 5 btrfs profile. In addition it is added some code as preparatory work for RAID 6 recovery code. Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> --- grub-core/fs/btrfs.c | 162 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 157 insertions(+), 5 deletions(-) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index 899dc32b7..d066d54cc 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -29,6 +29,7 @@ #include <minilzo.h> #include <grub/i18n.h> #include <grub/btrfs.h> +#include <grub/crypto.h> GRUB_MOD_LICENSE ("GPLv3+"); @@ -665,6 +666,141 @@ btrfs_read_from_chunk (struct grub_btrfs_data *data, return err; } +struct raid56_buffer { + void *buf; + int data_is_valid; +}; + +static void +rebuild_raid5 (char *dest, struct raid56_buffer *buffers, + grub_uint64_t nstripes, grub_uint64_t csize) +{ + grub_uint64_t i; + int first; + + for(i = 0; buffers[i].data_is_valid && i < nstripes; i++); + + if (i == nstripes) + { + grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n"); + return; + } + + grub_dprintf ("btrfs", "rebuilding RAID 5 stripe #%" PRIuGRUB_UINT64_T "\n", i); + + for (i = 0, first = 1; i < nstripes; i++) + { + if (!buffers[i].data_is_valid) + continue; + + if (first) { + grub_memcpy(dest, buffers[i].buf, csize); + first = 0; + } else + grub_crypto_xor (dest, dest, buffers[i].buf, csize); + + } +} + +static grub_err_t +raid56_read_retry (struct grub_btrfs_data *data, + struct grub_btrfs_chunk_item *chunk, + grub_uint64_t stripe_offset, + grub_uint64_t csize, void *buf) +{ + struct raid56_buffer *buffers; + grub_uint64_t nstripes = grub_le_to_cpu16 (chunk->nstripes); + grub_uint64_t chunk_type = grub_le_to_cpu64 (chunk->type); + grub_err_t ret = GRUB_ERR_OUT_OF_MEMORY; + grub_uint64_t i, failed_devices; + + buffers = grub_zalloc (sizeof(*buffers) * nstripes); + if (!buffers) + goto cleanup; + + for (i = 0; i < nstripes; i++) + { + buffers[i].buf = grub_zalloc (csize); + if (!buffers[i].buf) + goto cleanup; + } + + for (failed_devices = 0, i = 0; i < nstripes; i++) + { + struct grub_btrfs_chunk_stripe *stripe; + grub_disk_addr_t paddr; + grub_device_t dev; + grub_err_t err; + + /* after the struct grub_btrfs_chunk_item, there is an array of + struct grub_btrfs_chunk_stripe */ + stripe = (struct grub_btrfs_chunk_stripe *) (chunk + 1) + i; + + paddr = grub_le_to_cpu64 (stripe->offset) + stripe_offset; + grub_dprintf ("btrfs", "reading paddr %" PRIxGRUB_UINT64_T + " from stripe ID %" PRIxGRUB_UINT64_T "\n", paddr, + stripe->device_id); + + dev = find_device (data, stripe->device_id); + if (!dev) + { + buffers[i].data_is_valid = 0; + grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T " FAILED (dev ID %" + PRIxGRUB_UINT64_T ")\n", i, stripe->device_id); + failed_devices++; + continue; + } + + err = grub_disk_read (dev->disk, paddr >> GRUB_DISK_SECTOR_BITS, + paddr & (GRUB_DISK_SECTOR_SIZE - 1), + csize, buffers[i].buf); + if (err == GRUB_ERR_NONE) + { + buffers[i].data_is_valid = 1; + grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T " Ok (dev ID %" + PRIxGRUB_UINT64_T ")\n", i, stripe->device_id); + } + else + { + buffers[i].data_is_valid = 0; + grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T + " FAILED (dev ID %" PRIxGRUB_UINT64_T ")\n", i, + stripe->device_id); + failed_devices++; + } + } + + if (failed_devices > 1 && (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5)) + { + grub_dprintf ("btrfs", + "not enough disks for RAID 5: total %" PRIuGRUB_UINT64_T + ", missing %" PRIuGRUB_UINT64_T "\n", + nstripes, failed_devices); + ret = GRUB_ERR_READ_ERROR; + goto cleanup; + } + else + grub_dprintf ("btrfs", + "enough disks for RAID 5 rebuilding: total %" + PRIuGRUB_UINT64_T ", missing %" PRIuGRUB_UINT64_T "\n", + nstripes, failed_devices); + + /* if these are enough, try to rebuild the data */ + if (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5) + rebuild_raid5 (buf, buffers, nstripes, csize); + else + grub_dprintf ("btrfs", "called rebuild_raid6(), NOT IMPLEMENTED\n"); + + ret = GRUB_ERR_NONE; + cleanup: + if (buffers) + for (i = 0; i < nstripes; i++) + grub_free(buffers[i].buf); + grub_free(buffers); + + return ret; +} + static grub_err_t grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, void *buf, grub_size_t size, int recursion_depth) @@ -742,6 +878,10 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, grub_uint16_t nstripes; unsigned redundancy = 1; unsigned i, j; + int is_raid56; + + is_raid56 = !!(grub_le_to_cpu64 (chunk->type) & + GRUB_BTRFS_CHUNK_TYPE_RAID5); if (grub_le_to_cpu64 (chunk->size) <= off) { @@ -921,17 +1061,29 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, grub_dprintf ("btrfs", "reading laddr 0x%" PRIxGRUB_UINT64_T "\n", addr); - for (i = 0; i < redundancy; i++) + if (!is_raid56) + for (i = 0; i < redundancy; i++) + { + err = btrfs_read_from_chunk (data, chunk, stripen, + stripe_offset, + i, /* redundancy */ + csize, buf); + if (!err) + break; + grub_errno = GRUB_ERR_NONE; + } + else { err = btrfs_read_from_chunk (data, chunk, stripen, stripe_offset, - i, /* redundancy */ + 0, /* no mirror */ csize, buf); - if (!err) - break; grub_errno = GRUB_ERR_NONE; + if (err) + err = raid56_read_retry (data, chunk, stripe_offset, + csize, buf); } - if (i != redundancy) + if (!err) break; } if (err) -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* Re: [PATCH 7/9] btrfs: Add support for recovery for a RAID 5 btrfs profiles. 2018-10-11 18:51 ` [PATCH 7/9] btrfs: Add support for recovery for a RAID 5 btrfs profiles Goffredo Baroncelli @ 2018-10-17 14:14 ` Daniel Kiper 0 siblings, 0 replies; 23+ messages in thread From: Daniel Kiper @ 2018-10-17 14:14 UTC (permalink / raw) To: Goffredo Baroncelli Cc: grub-devel, Daniel Kiper, linux-btrfs, Goffredo Baroncelli On Thu, Oct 11, 2018 at 08:51:01PM +0200, Goffredo Baroncelli wrote: > From: Goffredo Baroncelli <kreijack@inwind.it> > > Add support for recovery for a RAID 5 btrfs profile. In addition > it is added some code as preparatory work for RAID 6 recovery code. > > Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> > --- > grub-core/fs/btrfs.c | 162 +++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 157 insertions(+), 5 deletions(-) > > diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c > index 899dc32b7..d066d54cc 100644 > --- a/grub-core/fs/btrfs.c > +++ b/grub-core/fs/btrfs.c > @@ -29,6 +29,7 @@ > #include <minilzo.h> > #include <grub/i18n.h> > #include <grub/btrfs.h> > +#include <grub/crypto.h> > > GRUB_MOD_LICENSE ("GPLv3+"); > > @@ -665,6 +666,141 @@ btrfs_read_from_chunk (struct grub_btrfs_data *data, > return err; > } > > +struct raid56_buffer { > + void *buf; > + int data_is_valid; > +}; > + > +static void > +rebuild_raid5 (char *dest, struct raid56_buffer *buffers, > + grub_uint64_t nstripes, grub_uint64_t csize) > +{ > + grub_uint64_t i; > + int first; > + > + for(i = 0; buffers[i].data_is_valid && i < nstripes; i++); > + > + if (i == nstripes) > + { > + grub_dprintf ("btrfs", "called rebuild_raid5(), but all disks are OK\n"); > + return; > + } > + > + grub_dprintf ("btrfs", "rebuilding RAID 5 stripe #%" PRIuGRUB_UINT64_T "\n", i); > + > + for (i = 0, first = 1; i < nstripes; i++) > + { > + if (!buffers[i].data_is_valid) > + continue; > + > + if (first) { > + grub_memcpy(dest, buffers[i].buf, csize); > + first = 0; > + } else > + grub_crypto_xor (dest, dest, buffers[i].buf, csize); > + Please drop this empty line. > + } > +} > + > +static grub_err_t > +raid56_read_retry (struct grub_btrfs_data *data, > + struct grub_btrfs_chunk_item *chunk, > + grub_uint64_t stripe_offset, > + grub_uint64_t csize, void *buf) > +{ > + struct raid56_buffer *buffers; > + grub_uint64_t nstripes = grub_le_to_cpu16 (chunk->nstripes); > + grub_uint64_t chunk_type = grub_le_to_cpu64 (chunk->type); > + grub_err_t ret = GRUB_ERR_OUT_OF_MEMORY; > + grub_uint64_t i, failed_devices; > + > + buffers = grub_zalloc (sizeof(*buffers) * nstripes); > + if (!buffers) > + goto cleanup; > + > + for (i = 0; i < nstripes; i++) > + { > + buffers[i].buf = grub_zalloc (csize); > + if (!buffers[i].buf) > + goto cleanup; > + } > + > + for (failed_devices = 0, i = 0; i < nstripes; i++) > + { > + struct grub_btrfs_chunk_stripe *stripe; > + grub_disk_addr_t paddr; > + grub_device_t dev; > + grub_err_t err; > + > + /* after the struct grub_btrfs_chunk_item, there is an array of > + struct grub_btrfs_chunk_stripe */ /* Struct grub_btrfs_chunk_stripe lives behind struct grub_btrfs_chunk_item. */ > + stripe = (struct grub_btrfs_chunk_stripe *) (chunk + 1) + i; > + > + paddr = grub_le_to_cpu64 (stripe->offset) + stripe_offset; > + grub_dprintf ("btrfs", "reading paddr %" PRIxGRUB_UINT64_T > + " from stripe ID %" PRIxGRUB_UINT64_T "\n", paddr, > + stripe->device_id); > + > + dev = find_device (data, stripe->device_id); > + if (!dev) > + { > + buffers[i].data_is_valid = 0; > + grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T " FAILED (dev ID %" > + PRIxGRUB_UINT64_T ")\n", i, stripe->device_id); > + failed_devices++; > + continue; > + } > + > + err = grub_disk_read (dev->disk, paddr >> GRUB_DISK_SECTOR_BITS, > + paddr & (GRUB_DISK_SECTOR_SIZE - 1), > + csize, buffers[i].buf); > + if (err == GRUB_ERR_NONE) > + { > + buffers[i].data_is_valid = 1; > + grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T " Ok (dev ID %" s/Ok/OK/ > + PRIxGRUB_UINT64_T ")\n", i, stripe->device_id); > + } > + else > + { > + buffers[i].data_is_valid = 0; > + grub_dprintf ("btrfs", "stripe %" PRIuGRUB_UINT64_T > + " FAILED (dev ID %" PRIxGRUB_UINT64_T ")\n", i, > + stripe->device_id); > + failed_devices++; > + } > + } > + > + if (failed_devices > 1 && (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5)) > + { > + grub_dprintf ("btrfs", > + "not enough disks for RAID 5: total %" PRIuGRUB_UINT64_T > + ", missing %" PRIuGRUB_UINT64_T "\n", > + nstripes, failed_devices); > + ret = GRUB_ERR_READ_ERROR; > + goto cleanup; > + } > + else > + grub_dprintf ("btrfs", > + "enough disks for RAID 5 rebuilding: total %" s/enough disks for RAID 5 rebuilding/enough disks for RAID 5/ > + PRIuGRUB_UINT64_T ", missing %" PRIuGRUB_UINT64_T "\n", > + nstripes, failed_devices); > + > + /* if these are enough, try to rebuild the data */ /* We have enough disks. So, rebuild the data. */ > + if (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5) > + rebuild_raid5 (buf, buffers, nstripes, csize); > + else > + grub_dprintf ("btrfs", "called rebuild_raid6(), NOT IMPLEMENTED\n"); > + > + ret = GRUB_ERR_NONE; > + cleanup: > + if (buffers) > + for (i = 0; i < nstripes; i++) > + grub_free(buffers[i].buf); Lack of space between function name and "(". > + grub_free(buffers); Ditto. > + return ret; > +} > + > static grub_err_t > grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, > void *buf, grub_size_t size, int recursion_depth) > @@ -742,6 +878,10 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, > grub_uint16_t nstripes; > unsigned redundancy = 1; > unsigned i, j; > + int is_raid56; > + > + is_raid56 = !!(grub_le_to_cpu64 (chunk->type) & > + GRUB_BTRFS_CHUNK_TYPE_RAID5); > > if (grub_le_to_cpu64 (chunk->size) <= off) > { > @@ -921,17 +1061,29 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, > grub_dprintf ("btrfs", "reading laddr 0x%" PRIxGRUB_UINT64_T "\n", > addr); > > - for (i = 0; i < redundancy; i++) > + if (!is_raid56) Why not "if (is_raid56)"? I asked about that earlier. Please change this if and of course code below. It will be much easier to read. And you do not need curly brackets for for loop after else. > + for (i = 0; i < redundancy; i++) > + { > + err = btrfs_read_from_chunk (data, chunk, stripen, > + stripe_offset, > + i, /* redundancy */ > + csize, buf); > + if (!err) > + break; > + grub_errno = GRUB_ERR_NONE; > + } > + else > { > err = btrfs_read_from_chunk (data, chunk, stripen, > stripe_offset, > - i, /* redundancy */ > + 0, /* no mirror */ > csize, buf); > - if (!err) > - break; > grub_errno = GRUB_ERR_NONE; > + if (err) > + err = raid56_read_retry (data, chunk, stripe_offset, > + csize, buf); > } > - if (i != redundancy) > + if (!err) > break; > } > if (err) Daniel ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 8/9] btrfs: Make more generic the code for RAID 6 rebuilding 2018-10-11 18:50 [PATCH V9] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli ` (6 preceding siblings ...) 2018-10-11 18:51 ` [PATCH 7/9] btrfs: Add support for recovery for a RAID 5 btrfs profiles Goffredo Baroncelli @ 2018-10-11 18:51 ` Goffredo Baroncelli 2018-10-11 18:51 ` [PATCH 9/9] btrfs: Add RAID 6 recovery for a btrfs filesystem Goffredo Baroncelli 8 siblings, 0 replies; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-11 18:51 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> The original code which handles the recovery of a RAID 6 disks array assumes that all reads are multiple of 1 << GRUB_DISK_SECTOR_BITS and it assumes that all the I/O is done via the struct grub_diskfilter_segment. This is not true for the btrfs code. In order to reuse the native grub_raid6_recover() code, it is modified to not call grub_diskfilter_read_node() directly, but to call an handler passed as an argument. Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/disk/raid6_recover.c | 52 ++++++++++++++++++++++------------ include/grub/diskfilter.h | 9 ++++++ 2 files changed, 43 insertions(+), 18 deletions(-) diff --git a/grub-core/disk/raid6_recover.c b/grub-core/disk/raid6_recover.c index aa674f6ca..0cf691ddf 100644 --- a/grub-core/disk/raid6_recover.c +++ b/grub-core/disk/raid6_recover.c @@ -74,14 +74,26 @@ mod_255 (unsigned x) } static grub_err_t -grub_raid6_recover (struct grub_diskfilter_segment *array, int disknr, int p, - char *buf, grub_disk_addr_t sector, grub_size_t size) +raid6_recover_read_node (void *data, int disknr, + grub_uint64_t sector, + void *buf, grub_size_t size) +{ + struct grub_diskfilter_segment *array = data; + + return grub_diskfilter_read_node (&array->nodes[disknr], + (grub_disk_addr_t)sector, + size >> GRUB_DISK_SECTOR_BITS, buf); +} + +grub_err_t +grub_raid6_recover_gen (void *data, grub_uint64_t nstripes, int disknr, int p, + char *buf, grub_uint64_t sector, grub_size_t size, + int layout, raid_recover_read_t read_func) { int i, q, pos; int bad1 = -1, bad2 = -1; char *pbuf = 0, *qbuf = 0; - size <<= GRUB_DISK_SECTOR_BITS; pbuf = grub_zalloc (size); if (!pbuf) goto quit; @@ -91,17 +103,17 @@ grub_raid6_recover (struct grub_diskfilter_segment *array, int disknr, int p, goto quit; q = p + 1; - if (q == (int) array->node_count) + if (q == (int) nstripes) q = 0; pos = q + 1; - if (pos == (int) array->node_count) + if (pos == (int) nstripes) pos = 0; - for (i = 0; i < (int) array->node_count - 2; i++) + for (i = 0; i < (int) nstripes - 2; i++) { int c; - if (array->layout & GRUB_RAID_LAYOUT_MUL_FROM_POS) + if (layout & GRUB_RAID_LAYOUT_MUL_FROM_POS) c = pos; else c = i; @@ -109,8 +121,7 @@ grub_raid6_recover (struct grub_diskfilter_segment *array, int disknr, int p, bad1 = c; else { - if (! grub_diskfilter_read_node (&array->nodes[pos], sector, - size >> GRUB_DISK_SECTOR_BITS, buf)) + if (!read_func(data, pos, sector, buf, size)) { grub_crypto_xor (pbuf, pbuf, buf, size); grub_raid_block_mulx (c, buf, size); @@ -128,7 +139,7 @@ grub_raid6_recover (struct grub_diskfilter_segment *array, int disknr, int p, } pos++; - if (pos == (int) array->node_count) + if (pos == (int) nstripes) pos = 0; } @@ -139,16 +150,14 @@ grub_raid6_recover (struct grub_diskfilter_segment *array, int disknr, int p, if (bad2 < 0) { /* One bad device */ - if ((! grub_diskfilter_read_node (&array->nodes[p], sector, - size >> GRUB_DISK_SECTOR_BITS, buf))) + if (!read_func(data, p, sector, buf, size)) { grub_crypto_xor (buf, buf, pbuf, size); goto quit; } grub_errno = GRUB_ERR_NONE; - if (grub_diskfilter_read_node (&array->nodes[q], sector, - size >> GRUB_DISK_SECTOR_BITS, buf)) + if (read_func(data, q, sector, buf, size)) goto quit; grub_crypto_xor (buf, buf, qbuf, size); @@ -160,14 +169,12 @@ grub_raid6_recover (struct grub_diskfilter_segment *array, int disknr, int p, /* Two bad devices */ unsigned c; - if (grub_diskfilter_read_node (&array->nodes[p], sector, - size >> GRUB_DISK_SECTOR_BITS, buf)) + if (read_func(data, p, sector, buf, size)) goto quit; grub_crypto_xor (pbuf, pbuf, buf, size); - if (grub_diskfilter_read_node (&array->nodes[q], sector, - size >> GRUB_DISK_SECTOR_BITS, buf)) + if (read_func(data, q, sector, buf, size)) goto quit; grub_crypto_xor (qbuf, qbuf, buf, size); @@ -190,6 +197,15 @@ quit: return grub_errno; } +static grub_err_t +grub_raid6_recover (struct grub_diskfilter_segment *array, int disknr, int p, + char *buf, grub_disk_addr_t sector, grub_size_t size) +{ + return grub_raid6_recover_gen (array, array->node_count, disknr, p, buf, + sector, size << GRUB_DISK_SECTOR_BITS, + array->layout, raid6_recover_read_node); +} + GRUB_MOD_INIT(raid6rec) { grub_raid6_init_table (); diff --git a/include/grub/diskfilter.h b/include/grub/diskfilter.h index d89273c1b..8deb1a8c3 100644 --- a/include/grub/diskfilter.h +++ b/include/grub/diskfilter.h @@ -189,6 +189,15 @@ typedef grub_err_t (*grub_raid6_recover_func_t) (struct grub_diskfilter_segment extern grub_raid5_recover_func_t grub_raid5_recover_func; extern grub_raid6_recover_func_t grub_raid6_recover_func; +typedef grub_err_t (* raid_recover_read_t)(void *data, int disk_nr, + grub_uint64_t addr, void *dest, + grub_size_t size); + +extern grub_err_t +grub_raid6_recover_gen (void *data, grub_uint64_t nstripes, int disknr, int p, + char *buf, grub_uint64_t sector, grub_size_t size, + int layout, raid_recover_read_t read_func); + grub_err_t grub_diskfilter_vg_register (struct grub_diskfilter_vg *vg); grub_err_t -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH 9/9] btrfs: Add RAID 6 recovery for a btrfs filesystem. 2018-10-11 18:50 [PATCH V9] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli ` (7 preceding siblings ...) 2018-10-11 18:51 ` [PATCH 8/9] btrfs: Make more generic the code for RAID 6 rebuilding Goffredo Baroncelli @ 2018-10-11 18:51 ` Goffredo Baroncelli 2018-10-17 14:23 ` Daniel Kiper 8 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-11 18:51 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> Add the RAID 6 recovery, in order to use a RAID 6 filesystem even if some disks (up to two) are missing. This code use the md RAID 6 code already present in grub. Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/fs/btrfs.c | 60 +++++++++++++++++++++++++++++++++++++++----- 1 file changed, 54 insertions(+), 6 deletions(-) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index d066d54cc..d20ee09e4 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -30,6 +30,7 @@ #include <grub/i18n.h> #include <grub/btrfs.h> #include <grub/crypto.h> +#include <grub/diskfilter.h> GRUB_MOD_LICENSE ("GPLv3+"); @@ -702,11 +703,36 @@ rebuild_raid5 (char *dest, struct raid56_buffer *buffers, } } +static grub_err_t +raid6_recover_read_buffer (void *data, int disk_nr, + grub_uint64_t addr __attribute__ ((unused)), + void *dest, grub_size_t size) +{ + struct raid56_buffer *buffers = data; + + if (!buffers[disk_nr].data_is_valid) + return grub_errno = GRUB_ERR_READ_ERROR; + + grub_memcpy(dest, buffers[disk_nr].buf, size); + + return grub_errno = GRUB_ERR_NONE; +} + +static void +rebuild_raid6 (struct raid56_buffer *buffers, grub_uint64_t nstripes, + grub_uint64_t csize, grub_uint64_t parities_pos, void *dest, + grub_uint64_t stripen) + +{ + grub_raid6_recover_gen (buffers, nstripes, stripen, parities_pos, + dest, 0, csize, 0, raid6_recover_read_buffer); +} + static grub_err_t raid56_read_retry (struct grub_btrfs_data *data, struct grub_btrfs_chunk_item *chunk, - grub_uint64_t stripe_offset, - grub_uint64_t csize, void *buf) + grub_uint64_t stripe_offset, grub_uint64_t stripen, + grub_uint64_t csize, void *buf, grub_uint64_t parities_pos) { struct raid56_buffer *buffers; grub_uint64_t nstripes = grub_le_to_cpu16 (chunk->nstripes); @@ -779,6 +805,15 @@ raid56_read_retry (struct grub_btrfs_data *data, ret = GRUB_ERR_READ_ERROR; goto cleanup; } + else if (failed_devices > 2 && (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID6)) + { + grub_dprintf ("btrfs", + "not enough disks for raid6: total %" PRIuGRUB_UINT64_T + ", missing %" PRIuGRUB_UINT64_T "\n", + nstripes, failed_devices); + ret = GRUB_ERR_READ_ERROR; + goto cleanup; + } else grub_dprintf ("btrfs", "enough disks for RAID 5 rebuilding: total %" @@ -789,7 +824,7 @@ raid56_read_retry (struct grub_btrfs_data *data, if (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5) rebuild_raid5 (buf, buffers, nstripes, csize); else - grub_dprintf ("btrfs", "called rebuild_raid6(), NOT IMPLEMENTED\n"); + rebuild_raid6 (buffers, nstripes, csize, parities_pos, buf, stripen); ret = GRUB_ERR_NONE; cleanup: @@ -879,9 +914,11 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, unsigned redundancy = 1; unsigned i, j; int is_raid56; + grub_uint64_t parities_pos = 0; - is_raid56 = !!(grub_le_to_cpu64 (chunk->type) & - GRUB_BTRFS_CHUNK_TYPE_RAID5); + is_raid56 = !!(grub_le_to_cpu64 (chunk->type) & + (GRUB_BTRFS_CHUNK_TYPE_RAID5 | + GRUB_BTRFS_CHUNK_TYPE_RAID6)); if (grub_le_to_cpu64 (chunk->size) <= off) { @@ -1030,6 +1067,17 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, */ grub_divmod64 (high + stripen, nstripes, &stripen); + /* + * parities_pos is equal to "(high - nparities) % nstripes" + * (see the diagram above). + * However "high - nparities" might be negative (eg when high + * == 0) leading to an incorrect computation. + * Instead "high + nstripes - nparities" is always positive and + * in modulo nstripes is equal to "(high - nparities) % nstripes" + */ + grub_divmod64 (high + nstripes - nparities, nstripes, + &parities_pos); + stripe_offset = low + chunk_stripe_length * high; csize = chunk_stripe_length - low; @@ -1081,7 +1129,7 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, grub_errno = GRUB_ERR_NONE; if (err) err = raid56_read_retry (data, chunk, stripe_offset, - csize, buf); + stripen, csize, buf, parities_pos); } if (!err) break; -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* Re: [PATCH 9/9] btrfs: Add RAID 6 recovery for a btrfs filesystem. 2018-10-11 18:51 ` [PATCH 9/9] btrfs: Add RAID 6 recovery for a btrfs filesystem Goffredo Baroncelli @ 2018-10-17 14:23 ` Daniel Kiper 0 siblings, 0 replies; 23+ messages in thread From: Daniel Kiper @ 2018-10-17 14:23 UTC (permalink / raw) To: Goffredo Baroncelli Cc: grub-devel, Daniel Kiper, linux-btrfs, Goffredo Baroncelli On Thu, Oct 11, 2018 at 08:51:03PM +0200, Goffredo Baroncelli wrote: > From: Goffredo Baroncelli <kreijack@inwind.it> > > Add the RAID 6 recovery, in order to use a RAID 6 filesystem even if some > disks (up to two) are missing. This code use the md RAID 6 code already > present in grub. > > Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> > Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> > --- > grub-core/fs/btrfs.c | 60 +++++++++++++++++++++++++++++++++++++++----- > 1 file changed, 54 insertions(+), 6 deletions(-) > > diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c > index d066d54cc..d20ee09e4 100644 > --- a/grub-core/fs/btrfs.c > +++ b/grub-core/fs/btrfs.c > @@ -30,6 +30,7 @@ > #include <grub/i18n.h> > #include <grub/btrfs.h> > #include <grub/crypto.h> > +#include <grub/diskfilter.h> > > GRUB_MOD_LICENSE ("GPLv3+"); > > @@ -702,11 +703,36 @@ rebuild_raid5 (char *dest, struct raid56_buffer *buffers, > } > } > > +static grub_err_t > +raid6_recover_read_buffer (void *data, int disk_nr, > + grub_uint64_t addr __attribute__ ((unused)), > + void *dest, grub_size_t size) > +{ > + struct raid56_buffer *buffers = data; > + > + if (!buffers[disk_nr].data_is_valid) > + return grub_errno = GRUB_ERR_READ_ERROR; > + > + grub_memcpy(dest, buffers[disk_nr].buf, size); > + > + return grub_errno = GRUB_ERR_NONE; > +} > + > +static void > +rebuild_raid6 (struct raid56_buffer *buffers, grub_uint64_t nstripes, > + grub_uint64_t csize, grub_uint64_t parities_pos, void *dest, > + grub_uint64_t stripen) > + > +{ > + grub_raid6_recover_gen (buffers, nstripes, stripen, parities_pos, > + dest, 0, csize, 0, raid6_recover_read_buffer); > +} > + > static grub_err_t > raid56_read_retry (struct grub_btrfs_data *data, > struct grub_btrfs_chunk_item *chunk, > - grub_uint64_t stripe_offset, > - grub_uint64_t csize, void *buf) > + grub_uint64_t stripe_offset, grub_uint64_t stripen, > + grub_uint64_t csize, void *buf, grub_uint64_t parities_pos) > { > struct raid56_buffer *buffers; > grub_uint64_t nstripes = grub_le_to_cpu16 (chunk->nstripes); > @@ -779,6 +805,15 @@ raid56_read_retry (struct grub_btrfs_data *data, > ret = GRUB_ERR_READ_ERROR; > goto cleanup; > } > + else if (failed_devices > 2 && (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID6)) > + { > + grub_dprintf ("btrfs", > + "not enough disks for raid6: total %" PRIuGRUB_UINT64_T s/not enough disks for raid6/not enough disks for RAID 6/ You are using "RAID 5" in earlier patch, so, please be consistent and use "RAID 6" here. > + ", missing %" PRIuGRUB_UINT64_T "\n", > + nstripes, failed_devices); > + ret = GRUB_ERR_READ_ERROR; > + goto cleanup; > + } > else > grub_dprintf ("btrfs", > "enough disks for RAID 5 rebuilding: total %" > @@ -789,7 +824,7 @@ raid56_read_retry (struct grub_btrfs_data *data, > if (chunk_type & GRUB_BTRFS_CHUNK_TYPE_RAID5) > rebuild_raid5 (buf, buffers, nstripes, csize); > else > - grub_dprintf ("btrfs", "called rebuild_raid6(), NOT IMPLEMENTED\n"); > + rebuild_raid6 (buffers, nstripes, csize, parities_pos, buf, stripen); > > ret = GRUB_ERR_NONE; > cleanup: > @@ -879,9 +914,11 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, > unsigned redundancy = 1; > unsigned i, j; > int is_raid56; > + grub_uint64_t parities_pos = 0; > > - is_raid56 = !!(grub_le_to_cpu64 (chunk->type) & > - GRUB_BTRFS_CHUNK_TYPE_RAID5); > + is_raid56 = !!(grub_le_to_cpu64 (chunk->type) & > + (GRUB_BTRFS_CHUNK_TYPE_RAID5 | > + GRUB_BTRFS_CHUNK_TYPE_RAID6)); > > if (grub_le_to_cpu64 (chunk->size) <= off) > { > @@ -1030,6 +1067,17 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, > */ > grub_divmod64 (high + stripen, nstripes, &stripen); > > + /* > + * parities_pos is equal to "(high - nparities) % nstripes" > + * (see the diagram above). > + * However "high - nparities" might be negative (eg when high > + * == 0) leading to an incorrect computation. However, "high - nparities" can be negative, eg. when high == 0, leading to an incorrect results. > + * Instead "high + nstripes - nparities" is always positive and > + * in modulo nstripes is equal to "(high - nparities) % nstripes" "high + nstripes - nparities" is always positive and modulo nstripes is equal to "(high - nparities) % nstripes". If you change above mentioned things you can retain my Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> Daniel ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH V11] Add support for BTRFS raid5/6 to GRUB @ 2018-10-22 17:29 Goffredo Baroncelli 2018-10-22 17:29 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli 0 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-22 17:29 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs Hi All, the aim of this patches set is to provide support for a BTRFS raid5/6 filesystem in GRUB. The first patch, implements the basic support for raid5/6. I.e this works when all the disks are present. The next 5 patches, are preparatory ones. The 7th patch implements the raid5 recovery for btrfs (i.e. handling the disappearing of 1 disk). The 8th patch makes the code for handling the raid6 recovery more generic. The last one implements the raid6 recovery for btrfs (i.e. handling the disappearing up to two disks). I tested the code in grub-emu, and it works both with all the disks, and with some disks missing. I checked the crc32 calculated from grub and from linux and these matched. Finally I checked if the support for md raid6 still works properly, and it does (with all drives and with up to 2 drives missing) Comments are welcome. Changelog v1: initial support for btrfs raid5/6. No recovery allowed v2: full support for btrfs raid5/6. Recovery allowed v3: some minor cleanup suggested by Daniel Kiper; reusing the original raid6 recovery code of grub v4: Several spell fix; better description of the RAID layout in btrfs, and the variables which describes the stripe positioning; split the patch #5 in two (#5 and #6) v5: Several spell fix; improved code comment in patch #1, small clean up in the code v6: Small cleanup; improved the wording in the RAID6 layout description; in the function raid6_recover_read_buffer() avoid a unnecessary memcpy in case of invalid data; v7: - patch 2,3,5,6,8 received an Review-by Daniel, and were unchanged from the last time (only minor cleanup in the commit description requested by Daniel) - patch 7 received some small update rearranging a for(), and some bracket around if() - patch 4, received an update message which explains better why NULL is stored in data->devices_attached[] - patch 9, received a blank line to separate better a code line from a previous comment. A description of 'parities_pos' was added - patch 1, received a major update about the variable meaning description in the comment. However I suspect that we need some further review to reach a fully agreement about this text. NB: the update are relate only to comments v8: - patch 2,5,6,8 received an Review-by Daniel, and were unchanged from the last time (only minor cleanup in the commit description requested by Daniel) - patch 1 received some adjustement to the variables description due to the different terminology between BTRFS and other RAID implementatio. Added a description for the "nparities" variable. - patch 3 removed some unnecessary curly brackets (change request by Daniel) - patch 4 received an improved commit description about why and how the function find_device() is changed - patch 7 received an update which transforms a i = 0; while(i..) i++; in for( i = 0..... ; i++); - patch 9 received an update to the comment v9: - patch 1: update comments - patch 4: update commit messages - patch 7: added a comment about accessing an array of structs after another structs; changed if(err == GRUB_ERR_NONE) in if(!err) changed if(err != GRUB_ERR_NONE) in if(err) v10:- patch 1: update comments (replace might with can) - patch 4: add a Signed off by Daniel - patch 7: drop an empty line; changed some text in grub_dprintf; reversed the logic of an if (if(!is_raid56) A else B -> if(is_raid5) B else A); add a space between the function name and the '(' - patch 9: update the wording in the comment; s/raid6/RAID 6/ in grub_dprintf() v11:- patch 7: removed redundant buffers[i].data_is_valid = 0; (2x); updated log messages (READ FAILED instead of FAILED) BR G.Baroncelli ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-10-22 17:29 [PATCH V11] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli @ 2018-10-22 17:29 ` Goffredo Baroncelli 0 siblings, 0 replies; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-22 17:29 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/fs/btrfs.c | 73 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index be195448d..9122169aa 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item #define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10 #define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20 #define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40 +#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80 +#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100 grub_uint8_t dummy2[0xc]; grub_uint16_t nstripes; grub_uint16_t nsubstripes; @@ -764,6 +766,77 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, stripe_offset = low + chunk_stripe_length * high; csize = chunk_stripe_length - low; + break; + } + case GRUB_BTRFS_CHUNK_TYPE_RAID5: + case GRUB_BTRFS_CHUNK_TYPE_RAID6: + { + grub_uint64_t nparities, stripe_nr, high, low; + + redundancy = 1; /* no redundancy for now */ + + if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5) + { + grub_dprintf ("btrfs", "RAID5\n"); + nparities = 1; + } + else + { + grub_dprintf ("btrfs", "RAID6\n"); + nparities = 2; + } + + /* + * RAID 6 layout consists of several stripes spread over + * the disks, e.g.: + * + * Disk_0 Disk_1 Disk_2 Disk_3 + * A0 B0 P0 Q0 + * Q1 A1 B1 P1 + * P2 Q2 A2 B2 + * + * Note: placement of the parities depend on row number. + * + * Pay attention that the btrfs terminology may differ from + * terminology used in other RAID implementations, e.g. LVM, + * dm or md. The main difference is that btrfs calls contiguous + * block of data on a given disk, e.g. A0, stripe instead of chunk. + * + * The variables listed below have following meaning: + * - stripe_nr is the stripe number excluding the parities + * (A0 = 0, B0 = 1, A1 = 2, B1 = 3, etc.), + * - high is the row number (0 for A0...Q0, 1 for Q1...P1, etc.), + * - stripen is the disk number in a row (0 for A0, Q1, P2, + * 1 for B0, A1, Q2, etc.), + * - off is the logical address to read, + * - chunk_stripe_length is the size of a stripe (typically 64 KiB), + * - nstripes is the number of disks in a row, + * - low is the offset of the data inside a stripe, + * - stripe_offset is the data offset in an array, + * - csize is the "potential" data to read; it will be reduced + * to size if the latter is smaller, + * - nparities is the number of parities (1 for RAID 5, 2 for + * RAID 6); used only in RAID 5/6 code. + */ + stripe_nr = grub_divmod64 (off, chunk_stripe_length, &low); + + /* + * stripen is computed without the parities + * (0 for A0, A1, A2, 1 for B0, B1, B2, etc.). + */ + high = grub_divmod64 (stripe_nr, nstripes - nparities, &stripen); + + /* + * The stripes are spread over the disks. Every each row their + * positions are shifted by 1 place. So, the real disks number + * change. Hence, we have to take into account current row number + * modulo nstripes (0 for A0, 1 for A1, 2 for A2, etc.). + */ + grub_divmod64 (high + stripen, nstripes, &stripen); + + stripe_offset = low + chunk_stripe_length * high; + csize = chunk_stripe_length - low; + break; } default: -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH V10] Add support for BTRFS raid5/6 to GRUB @ 2018-10-18 17:55 Goffredo Baroncelli 2018-10-18 17:55 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli 0 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-18 17:55 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs Hi All, the aim of this patches set is to provide support for a BTRFS raid5/6 filesystem in GRUB. The first patch, implements the basic support for raid5/6. I.e this works when all the disks are present. The next 5 patches, are preparatory ones. The 7th patch implements the raid5 recovery for btrfs (i.e. handling the disappearing of 1 disk). The 8th patch makes the code for handling the raid6 recovery more generic. The last one implements the raid6 recovery for btrfs (i.e. handling the disappearing up to two disks). I tested the code in grub-emu, and it works both with all the disks, and with some disks missing. I checked the crc32 calculated from grub and from linux and these matched. Finally I checked if the support for md raid6 still works properly, and it does (with all drives and with up to 2 drives missing) Comments are welcome. Changelog v1: initial support for btrfs raid5/6. No recovery allowed v2: full support for btrfs raid5/6. Recovery allowed v3: some minor cleanup suggested by Daniel Kiper; reusing the original raid6 recovery code of grub v4: Several spell fix; better description of the RAID layout in btrfs, and the variables which describes the stripe positioning; split the patch #5 in two (#5 and #6) v5: Several spell fix; improved code comment in patch #1, small clean up in the code v6: Small cleanup; improved the wording in the RAID6 layout description; in the function raid6_recover_read_buffer() avoid a unnecessary memcpy in case of invalid data; v7: - patch 2,3,5,6,8 received an Review-by Daniel, and were unchanged from the last time (only minor cleanup in the commit description requested by Daniel) - patch 7 received some small update rearranging a for(), and some bracket around if() - patch 4, received an update message which explains better why NULL is stored in data->devices_attached[] - patch 9, received a blank line to separate better a code line from a previous comment. A description of 'parities_pos' was added - patch 1, received a major update about the variable meaning description in the comment. However I suspect that we need some further review to reach a fully agreement about this text. NB: the update are relate only to comments v8: - patch 2,5,6,8 received an Review-by Daniel, and were unchanged from the last time (only minor cleanup in the commit description requested by Daniel) - patch 1 received some adjustement to the variables description due to the different terminology between BTRFS and other RAID implementatio. Added a description for the "nparities" variable. - patch 3 removed some unnecessary curly brackets (change request by Daniel) - patch 4 received an improved commit description about why and how the function find_device() is changed - patch 7 received an update which transforms a i = 0; while(i..) i++; in for( i = 0..... ; i++); - patch 9 received an update to the comment v9: - patch 1: update comments - patch 4: update commit messages - patch 7: added a comment about accessing an array of structs after another structs; changed if(err == GRUB_ERR_NONE) in if(!err) changed if(err != GRUB_ERR_NONE) in if(err) v10:- patch 1: update comments (replace might with can) - patch 4: add a Signed off by Daniel - patch 7: drop an empty line; changed some text in grub_dprintf; reversed the logic of an if (if(!is_raid56) A else B -> if(is_raid5) B else A); add a space between the function name and the '(' - patch 9: update the wording in the comment; s/raid6/RAID 6/ in grub_dprintf() BR G.Baroncelli -- gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-10-18 17:55 [PATCH V10] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli @ 2018-10-18 17:55 ` Goffredo Baroncelli 0 siblings, 0 replies; 23+ messages in thread From: Goffredo Baroncelli @ 2018-10-18 17:55 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/fs/btrfs.c | 73 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index be195448d..9122169aa 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item #define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10 #define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20 #define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40 +#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80 +#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100 grub_uint8_t dummy2[0xc]; grub_uint16_t nstripes; grub_uint16_t nsubstripes; @@ -764,6 +766,77 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, stripe_offset = low + chunk_stripe_length * high; csize = chunk_stripe_length - low; + break; + } + case GRUB_BTRFS_CHUNK_TYPE_RAID5: + case GRUB_BTRFS_CHUNK_TYPE_RAID6: + { + grub_uint64_t nparities, stripe_nr, high, low; + + redundancy = 1; /* no redundancy for now */ + + if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5) + { + grub_dprintf ("btrfs", "RAID5\n"); + nparities = 1; + } + else + { + grub_dprintf ("btrfs", "RAID6\n"); + nparities = 2; + } + + /* + * RAID 6 layout consists of several stripes spread over + * the disks, e.g.: + * + * Disk_0 Disk_1 Disk_2 Disk_3 + * A0 B0 P0 Q0 + * Q1 A1 B1 P1 + * P2 Q2 A2 B2 + * + * Note: placement of the parities depend on row number. + * + * Pay attention that the btrfs terminology may differ from + * terminology used in other RAID implementations, e.g. LVM, + * dm or md. The main difference is that btrfs calls contiguous + * block of data on a given disk, e.g. A0, stripe instead of chunk. + * + * The variables listed below have following meaning: + * - stripe_nr is the stripe number excluding the parities + * (A0 = 0, B0 = 1, A1 = 2, B1 = 3, etc.), + * - high is the row number (0 for A0...Q0, 1 for Q1...P1, etc.), + * - stripen is the disk number in a row (0 for A0, Q1, P2, + * 1 for B0, A1, Q2, etc.), + * - off is the logical address to read, + * - chunk_stripe_length is the size of a stripe (typically 64 KiB), + * - nstripes is the number of disks in a row, + * - low is the offset of the data inside a stripe, + * - stripe_offset is the data offset in an array, + * - csize is the "potential" data to read; it will be reduced + * to size if the latter is smaller, + * - nparities is the number of parities (1 for RAID 5, 2 for + * RAID 6); used only in RAID 5/6 code. + */ + stripe_nr = grub_divmod64 (off, chunk_stripe_length, &low); + + /* + * stripen is computed without the parities + * (0 for A0, A1, A2, 1 for B0, B1, B2, etc.). + */ + high = grub_divmod64 (stripe_nr, nstripes - nparities, &stripen); + + /* + * The stripes are spread over the disks. Every each row their + * positions are shifted by 1 place. So, the real disks number + * change. Hence, we have to take into account current row number + * modulo nstripes (0 for A0, 1 for A1, 2 for A2, etc.). + */ + grub_divmod64 (high + stripen, nstripes, &stripen); + + stripe_offset = low + chunk_stripe_length * high; + csize = chunk_stripe_length - low; + break; } default: -- 2.19.1 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH V8] Add support for BTRFS raid5/6 to GRUB @ 2018-09-27 18:34 Goffredo Baroncelli 2018-09-27 18:34 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli 0 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-09-27 18:34 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs i All, the aim of this patches set is to provide support for a BTRFS raid5/6 filesystem in GRUB. The first patch, implements the basic support for raid5/6. I.e this works when all the disks are present. The next 5 patches, are preparatory ones. The 7th patch implements the raid5 recovery for btrfs (i.e. handling the disappearing of 1 disk). The 8th patch makes the code for handling the raid6 recovery more generic. The last one implements the raid6 recovery for btrfs (i.e. handling the disappearing up to two disks). I tested the code in grub-emu, and it works both with all the disks, and with some disks missing. I checked the crc32 calculated from grub and from linux and these matched. Finally I checked if the support for md raid6 still works properly, and it does (with all drives and with up to 2 drives missing) Comments are welcome. Changelog v1: initial support for btrfs raid5/6. No recovery allowed v2: full support for btrfs raid5/6. Recovery allowed v3: some minor cleanup suggested by Daniel Kiper; reusing the original raid6 recovery code of grub v4: Several spell fix; better description of the RAID layout in btrfs, and the variables which describes the stripe positioning; split the patch #5 in two (#5 and #6) v5: Several spell fix; improved code comment in patch #1, small clean up in the code v6: Small cleanup; improved the wording in the RAID6 layout description; in the function raid6_recover_read_buffer() avoid a unnecessary memcpy in case of invalid data; v7: - patch 2,3,5,6,8 received an Review-by Daniel, and were unchanged from the last time (only minor cleanup in the commit description requested by Daniel) - patch 7 received some small update rearranging a for(), and some bracket around if() - patch 4, received an update message which explains better why NULL is stored in data->devices_attached[] - patch 9, received a blank line to separate better a code line from a previous comment. A description of 'parities_pos' was added - patch 1, received a major update about the variable meaning description in the comment. However I suspect that we need some further review to reach a fully agreement about this text. NB: the update are relate only to comments v8: - patch 2,5,6,8 received an Review-by Daniel, and were unchanged from the last time (only minor cleanup in the commit description requested by Daniel) - patch 1 received some adjustement to the variables description due to the different terminology between BTRFS and other RAID implementatio. Added a description for the "nparities" variable. - patch 3 removed some unnecessary curly brackets (change request by Daniel) - patch 4 received an improved commit description about why and how the function find_device() is changed - patch 7 received an update which transforms a i = 0; while(i..) i++; in for( i = 0..... ; i++); - patch 9 received an update to the comment BR G.Baroncelli -- gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-09-27 18:34 [PATCH V8] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli @ 2018-09-27 18:34 ` Goffredo Baroncelli 2018-10-09 17:51 ` Daniel Kiper 0 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-09-27 18:34 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> --- grub-core/fs/btrfs.c | 74 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index be195448d..9bc6d399d 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item #define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10 #define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20 #define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40 +#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80 +#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100 grub_uint8_t dummy2[0xc]; grub_uint16_t nstripes; grub_uint16_t nsubstripes; @@ -764,6 +766,78 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, stripe_offset = low + chunk_stripe_length * high; csize = chunk_stripe_length - low; + break; + } + case GRUB_BTRFS_CHUNK_TYPE_RAID5: + case GRUB_BTRFS_CHUNK_TYPE_RAID6: + { + grub_uint64_t nparities, stripe_nr, high, low; + + redundancy = 1; /* no redundancy for now */ + + if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5) + { + grub_dprintf ("btrfs", "RAID5\n"); + nparities = 1; + } + else + { + grub_dprintf ("btrfs", "RAID6\n"); + nparities = 2; + } + + /* + * A RAID 6 layout consists of several stripes spread on the + * disks, following a layout like the one below + * + * Disk0 Disk1 Disk2 Disk3 + * + * A1 B1 P1 Q1 + * Q2 A2 B2 P2 + * P3 Q3 A3 B3 + * [...] + * + * Note that the placement of the parities depends on row index. + * Pay attention that the BTRFS terminolgy may be different + * from others RAID implementation (e.g. lvm/dm or md). In BTRFS + * a contiguous block of data of a disk (like A1) is called + * stripe. + * In the code below: + * - stripe_nr is the stripe number without the parities + * (A1 = 0, B1 = 1, A2 = 2, B2 = 3, ...), + * - high is the row number (0 for A1...Q1, 1 for Q2...P2, ...), + * - stripen is the disk number in a row (0 for A1,Q2,P3, 1 for + * B1...), + * - off is the logical address to read, + * - chunk_stripe_length is the size of a stripe (typically 64k), + * - nstripes is the number of disks of a row + * - low is the offset of the data inside a stripe, + * - stripe_offset is the data offset in an array, + * - csize is the "potential" data to read. It will be reduced to + * size if the latter is smaller. + * - nparities is the number of parities (1 for RAID5, 2 for + * RAID6); used only in RAID5/6 code. + */ + stripe_nr = grub_divmod64 (off, chunk_stripe_length, &low); + + /* + * stripen is computed without the parities (0 for A1, A2, A3... + * 1 for B1, B2...). + */ + high = grub_divmod64 (stripe_nr, nstripes - nparities, &stripen); + + /* + * the stripes are spread across the disks, each row their + * position is shifted by 1 place. So to compute the real disk + * number occuped by a stripe, we need to sum also the + * "row number" in modulo nstripes (0 for A1, 1 for A2, 2 for + * A3....). + */ + grub_divmod64 (high + stripen, nstripes, &stripen); + + stripe_offset = low + chunk_stripe_length * high; + csize = chunk_stripe_length - low; + break; } default: -- 2.19.0 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* Re: [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-09-27 18:34 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli @ 2018-10-09 17:51 ` Daniel Kiper 2018-10-11 13:17 ` Daniel Kiper 0 siblings, 1 reply; 23+ messages in thread From: Daniel Kiper @ 2018-10-09 17:51 UTC (permalink / raw) To: Goffredo Baroncelli Cc: grub-devel, Daniel Kiper, linux-btrfs, Goffredo Baroncelli On Thu, Sep 27, 2018 at 08:34:56PM +0200, Goffredo Baroncelli wrote: > From: Goffredo Baroncelli <kreijack@inwind.it> > > Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Code LGTM. Though comment begs improvement. I will send you updated comment for approval shortly. Daniel ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-10-09 17:51 ` Daniel Kiper @ 2018-10-11 13:17 ` Daniel Kiper 0 siblings, 0 replies; 23+ messages in thread From: Daniel Kiper @ 2018-10-11 13:17 UTC (permalink / raw) To: kreijack; +Cc: dkiper, grub-devel, linux-btrfs, Goffredo Baroncelli On Tue, Oct 09, 2018 at 07:51:01PM +0200, Daniel Kiper wrote: > On Thu, Sep 27, 2018 at 08:34:56PM +0200, Goffredo Baroncelli wrote: > > From: Goffredo Baroncelli <kreijack@inwind.it> > > > > Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> > > Code LGTM. Though comment begs improvement. I will send you updated > comment for approval shortly. Below you can find updated patch. Please check I have not messed up something. Daniel From ecefb12a10d39bdd09e1d2b8fbbcbdb1b35274f8 Mon Sep 17 00:00:00 2001 From: Goffredo Baroncelli <kreijack@inwind.it> Date: Thu, 27 Sep 2018 20:34:56 +0200 Subject: [PATCH 1/1] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com> --- grub-core/fs/btrfs.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index be19544..933a57d 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item #define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10 #define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20 #define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40 +#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80 +#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100 grub_uint8_t dummy2[0xc]; grub_uint16_t nstripes; grub_uint16_t nsubstripes; @@ -766,6 +768,77 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, csize = chunk_stripe_length - low; break; } + case GRUB_BTRFS_CHUNK_TYPE_RAID5: + case GRUB_BTRFS_CHUNK_TYPE_RAID6: + { + grub_uint64_t nparities, stripe_nr, high, low; + + redundancy = 1; /* no redundancy for now */ + + if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5) + { + grub_dprintf ("btrfs", "RAID5\n"); + nparities = 1; + } + else + { + grub_dprintf ("btrfs", "RAID6\n"); + nparities = 2; + } + + /* + * RAID 6 layout consists of several stripes spread over + * the disks, e.g.: + * + * Disk_0 Disk_1 Disk_2 Disk_3 + * A0 B0 P0 Q0 + * Q1 A1 B1 P1 + * P2 Q2 A2 B2 + * + * Note: placement of the parities depend on row number. + * + * Pay attention that the btrfs terminology may differ from + * terminology used in other RAID implementations, e.g. LVM, + * dm or md. The main difference is that btrfs calls contiguous + * block of data on a given disk, e.g. A0, stripe instead of chunk. + * + * The variables listed below have following meaning: + * - stripe_nr is the stripe number excluding the parities + * (A0 = 0, B0 = 1, A1 = 2, B1 = 3, etc.), + * - high is the row number (0 for A0...Q0, 1 for Q1...P1, etc.), + * - stripen is the disk number in a row (0 for A0, Q1, P2, + * 1 for B0, A1, Q2, etc.), + * - off is the logical address to read, + * - chunk_stripe_length is the size of a stripe (typically 64 KiB), + * - nstripes is the number of disks in a row, + * - low is the offset of the data inside a stripe, + * - stripe_offset is the data offset in an array, + * - csize is the "potential" data to read; it will be reduced + * to size if the latter is smaller, + * - nparities is the number of parities (1 for RAID 5, 2 for + * RAID 6); used only in RAID 5/6 code. + */ + stripe_nr = grub_divmod64 (off, chunk_stripe_length, &low); + + /* + * stripen is computed without the parities + * (0 for A0, A1, A2, 1 for B0, B1, B2, etc.). + */ + high = grub_divmod64 (stripe_nr, nstripes - nparities, &stripen); + + /* + * The stripes are spread over the disks. Every each row their + * positions are shifted by 1 place. So, the real disks number + * change. Hence, we have to take current row number modulo + * nstripes into account (0 for A0, 1 for A1, 2 for A2, etc.). + */ + grub_divmod64 (high + stripen, nstripes, &stripen); + + stripe_offset = low + chunk_stripe_length * high; + csize = chunk_stripe_length - low; + + break; + } default: grub_dprintf ("btrfs", "unsupported RAID\n"); return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, -- 1.7.10.4 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* [PATCH V7] Add support for BTRFS raid5/6 to GRUB @ 2018-09-19 18:40 Goffredo Baroncelli 2018-09-19 18:40 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli 0 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-09-19 18:40 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs Hi All, the aim of this patches set is to provide support for a BTRFS raid5/6 filesystem in GRUB. The first patch, implements the basic support for raid5/6. I.e this works when all the disks are present. The next 5 patches, are preparatory ones. The 7th patch implements the raid5 recovery for btrfs (i.e. handling the disappearing of 1 disk). The 8th patch makes the code for handling the raid6 recovery more generic. The last one implements the raid6 recovery for btrfs (i.e. handling the disappearing up to two disks). I tested the code in grub-emu, and it works both with all the disks, and with some disks missing. I checked the crc32 calculated from grub and from linux and these matched. Finally I checked if the support for md raid6 still works properly, and it does (with all drives and with up to 2 drives missing) Comments are welcome. Changelog v1: initial support for btrfs raid5/6. No recovery allowed v2: full support for btrfs raid5/6. Recovery allowed v3: some minor cleanup suggested by Daniel Kiper; reusing the original raid6 recovery code of grub v4: Several spell fix; better description of the RAID layout in btrfs, and the variables which describes the stripe positioning; split the patch #5 in two (#5 and #6) v5: Several spell fix; improved code comment in patch #1, small clean up in the code v6: Small cleanup; improved the wording in the RAID6 layout description; in the function raid6_recover_read_buffer() avoid a unnecessary memcpy in case of invalid data; v7: - patch 2,3,5,6,8 received an Review-by Daniel, and were unchanged from the last time (only minor cleanup in the commit description requested by Daniel) - patch 7 received some small update rearranging a for(), and some bracket around if() - patch 4, received an update message which explains better why NULL is stored in data->devices_attached[] - patch 9, received a blank line to separate better a code line from a previous comment. A description of 'parities_pos' was added - patch 1, received a major update about the variable meaning description in the comment. However I suspect that we need some further review to reach a fully agreement about this text. NB: the update are relate only to comments BR G.Baroncelli -- gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 ^ permalink raw reply [flat|nested] 23+ messages in thread
* [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-09-19 18:40 [PATCH V7] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli @ 2018-09-19 18:40 ` Goffredo Baroncelli 2018-09-25 15:31 ` Daniel Kiper 0 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-09-19 18:40 UTC (permalink / raw) To: grub-devel; +Cc: Daniel Kiper, linux-btrfs, Goffredo Baroncelli From: Goffredo Baroncelli <kreijack@inwind.it> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> --- grub-core/fs/btrfs.c | 66 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index be195448d..56c42746d 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item #define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10 #define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20 #define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40 +#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80 +#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100 grub_uint8_t dummy2[0xc]; grub_uint16_t nstripes; grub_uint16_t nsubstripes; @@ -764,6 +766,70 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, stripe_offset = low + chunk_stripe_length * high; csize = chunk_stripe_length - low; + break; + } + case GRUB_BTRFS_CHUNK_TYPE_RAID5: + case GRUB_BTRFS_CHUNK_TYPE_RAID6: + { + grub_uint64_t nparities, block_nr, high, low; + + redundancy = 1; /* no redundancy for now */ + + if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5) + { + grub_dprintf ("btrfs", "RAID5\n"); + nparities = 1; + } + else + { + grub_dprintf ("btrfs", "RAID6\n"); + nparities = 2; + } + + /* + * A RAID 6 layout consists of several blocks spread on the disks. + * The raid terminology is used to call all the blocks of a row + * "stripe". Unfortunately the BTRFS terminology confuses block + * and stripe. + * + * Disk0 Disk1 Disk2 Disk3 + * + * A1 B1 P1 Q1 + * Q2 A2 B2 P2 + * P3 Q3 A3 B3 + * [...] + * + * Note that the placement of the parities depends on row index. + * In the code below: + * - block_nr is the block number without the parities + * (A1 = 0, B1 = 1, A2 = 2, B2 = 3, ...), + * - high is the row number (0 for A1...Q1, 1 for Q2...P2, ...), + * - stripen is the disk number (0 for A1,Q2,P3, 1 for B1...), + * - off is the logical address to read + * - chunk_stripe_length is the size of a block (typically 64k), + * - nstripes is the number of disks, + * - low is the offset of the data inside a stripe, + * - stripe_offset is the disk offset, + * - csize is the "potential" data to read. It will be reduced to + * size if the latter is smaller. + */ + block_nr = grub_divmod64 (off, chunk_stripe_length, &low); + + /* + * stripen is computed without the parities (0 for A1, A2, A3... + * 1 for B1, B2...). + */ + high = grub_divmod64 (block_nr, nstripes - nparities, &stripen); + + /* + * stripen is recomputed considering the parities (0 for A1, 1 for + * A2, 2 for A3....). + */ + grub_divmod64 (high + stripen, nstripes, &stripen); + + stripe_offset = low + chunk_stripe_length * high; + csize = chunk_stripe_length - low; + break; } default: -- 2.19.0 ^ permalink raw reply related [flat|nested] 23+ messages in thread
* Re: [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-09-19 18:40 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli @ 2018-09-25 15:31 ` Daniel Kiper 2018-09-26 20:40 ` Goffredo Baroncelli 0 siblings, 1 reply; 23+ messages in thread From: Daniel Kiper @ 2018-09-25 15:31 UTC (permalink / raw) To: Goffredo Baroncelli Cc: grub-devel, Daniel Kiper, linux-btrfs, Goffredo Baroncelli On Wed, Sep 19, 2018 at 08:40:32PM +0200, Goffredo Baroncelli wrote: > From: Goffredo Baroncelli <kreijack@inwind.it> > > Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> > --- > grub-core/fs/btrfs.c | 66 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 66 insertions(+) > > diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c > index be195448d..56c42746d 100644 > --- a/grub-core/fs/btrfs.c > +++ b/grub-core/fs/btrfs.c > @@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item > #define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10 > #define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20 > #define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40 > +#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80 > +#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100 > grub_uint8_t dummy2[0xc]; > grub_uint16_t nstripes; > grub_uint16_t nsubstripes; > @@ -764,6 +766,70 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, > stripe_offset = low + chunk_stripe_length > * high; > csize = chunk_stripe_length - low; > + break; > + } > + case GRUB_BTRFS_CHUNK_TYPE_RAID5: > + case GRUB_BTRFS_CHUNK_TYPE_RAID6: > + { > + grub_uint64_t nparities, block_nr, high, low; > + > + redundancy = 1; /* no redundancy for now */ > + > + if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5) > + { > + grub_dprintf ("btrfs", "RAID5\n"); > + nparities = 1; > + } > + else > + { > + grub_dprintf ("btrfs", "RAID6\n"); > + nparities = 2; > + } > + > + /* > + * A RAID 6 layout consists of several blocks spread on the disks. > + * The raid terminology is used to call all the blocks of a row > + * "stripe". Unfortunately the BTRFS terminology confuses block Stripe is data set or parity (parity stripe) on one disk. Block has different meaning. Please stick to btrfs terminology and say it clearly in the comment. And even add a link to btrfs wiki page to ease reading. I think about this one: https://btrfs.wiki.kernel.org/index.php/Manpage/mkfs.btrfs#BLOCK_GROUPS.2C_CHUNKS.2C_RAID > + * and stripe. I do not think so. Or at least not so much... > + * > + * Disk0 Disk1 Disk2 Disk3 > + * > + * A1 B1 P1 Q1 > + * Q2 A2 B2 P2 > + * P3 Q3 A3 B3 > + * [...] > + * > + * Note that the placement of the parities depends on row index. > + * In the code below: > + * - block_nr is the block number without the parities Well, it seems to me that the btrfs code introduces confusion not the spec itself. I would leave code as is but s/block number/stripe number/. > + * (A1 = 0, B1 = 1, A2 = 2, B2 = 3, ...), > + * - high is the row number (0 for A1...Q1, 1 for Q2...P2, ...), > + * - stripen is the disk number (0 for A1,Q2,P3, 1 for B1...), s/disk number/disk number in a row/ > + * - off is the logical address to read > + * - chunk_stripe_length is the size of a block (typically 64k), s/a block/a stripe/ > + * - nstripes is the number of disks, s/number of disks/number of disks in a row/ I miss the description of nparities here... > + * - low is the offset of the data inside a stripe, > + * - stripe_offset is the disk offset, s/the disk offset/the data offset in an array/? > + * - csize is the "potential" data to read. It will be reduced to > + * size if the latter is smaller. > + */ > + block_nr = grub_divmod64 (off, chunk_stripe_length, &low); > + > + /* > + * stripen is computed without the parities (0 for A1, A2, A3... > + * 1 for B1, B2...). > + */ > + high = grub_divmod64 (block_nr, nstripes - nparities, &stripen); This is clear... > + /* > + * stripen is recomputed considering the parities (0 for A1, 1 for > + * A2, 2 for A3....). > + */ > + grub_divmod64 (high + stripen, nstripes, &stripen); ... but this looks strange... You add disk number to row number. Hmmm... It looks that it works but this is not obvious at first sight. Could you explain that? > + stripe_offset = low + chunk_stripe_length * high; > + csize = chunk_stripe_length - low; > + > break; > } > default: Daniel ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-09-25 15:31 ` Daniel Kiper @ 2018-09-26 20:40 ` Goffredo Baroncelli 2018-09-27 15:47 ` Daniel Kiper 0 siblings, 1 reply; 23+ messages in thread From: Goffredo Baroncelli @ 2018-09-26 20:40 UTC (permalink / raw) To: Daniel Kiper; +Cc: grub-devel, linux-btrfs, Goffredo Baroncelli On 25/09/2018 17.31, Daniel Kiper wrote: > On Wed, Sep 19, 2018 at 08:40:32PM +0200, Goffredo Baroncelli wrote: >> From: Goffredo Baroncelli <kreijack@inwind.it> >> >> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> >> --- >> grub-core/fs/btrfs.c | 66 ++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 66 insertions(+) >> >> diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c >> index be195448d..56c42746d 100644 >> --- a/grub-core/fs/btrfs.c >> +++ b/grub-core/fs/btrfs.c >> @@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item >> #define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10 >> #define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20 >> #define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40 >> +#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80 >> +#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100 >> grub_uint8_t dummy2[0xc]; >> grub_uint16_t nstripes; >> grub_uint16_t nsubstripes; >> @@ -764,6 +766,70 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, >> stripe_offset = low + chunk_stripe_length >> * high; >> csize = chunk_stripe_length - low; >> + break; >> + } >> + case GRUB_BTRFS_CHUNK_TYPE_RAID5: >> + case GRUB_BTRFS_CHUNK_TYPE_RAID6: >> + { >> + grub_uint64_t nparities, block_nr, high, low; >> + >> + redundancy = 1; /* no redundancy for now */ >> + >> + if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5) >> + { >> + grub_dprintf ("btrfs", "RAID5\n"); >> + nparities = 1; >> + } >> + else >> + { >> + grub_dprintf ("btrfs", "RAID6\n"); >> + nparities = 2; >> + } >> + >> + /* >> + * A RAID 6 layout consists of several blocks spread on the disks. >> + * The raid terminology is used to call all the blocks of a row >> + * "stripe". Unfortunately the BTRFS terminology confuses block > > Stripe is data set or parity (parity stripe) on one disk. Block has > different meaning. Please stick to btrfs terminology and say it clearly > in the comment. And even add a link to btrfs wiki page to ease reading. > > I think about this one: > https://btrfs.wiki.kernel.org/index.php/Manpage/mkfs.btrfs#BLOCK_GROUPS.2C_CHUNKS.2C_RAID > >> + * and stripe. > > I do not think so. Or at least not so much... Trust me, generally speaking stripe is the "row" in the disks (without the parity); looking at the ext3 man page: .... stride=stride-size Configure the filesystem for a RAID array with stride-size filesystem blocks. This is the number of blocks read or written to disk before moving to the next disk, which is sometimes referred to as the chunk size. This mostly affects placement of filesystem metadata like bitmaps at mke2fs time to avoid placing them on a single disk, which can hurt performance. It may also be used by the block allo‐ cator. stripe_width=stripe-width Configure the filesystem for a RAID array with stripe-width filesystem blocks per stripe. This is typically stride-size * N, where N is the number of data-bearing disks in the RAID (e.g. for RAID 5 there is one parity disk, so N will be the number of disks in the array minus 1). This allows the block allocator to prevent read-modify-write of the parity in a RAID stripe if possible when the data is writ‐ ten. .... Looking at the RAID5 wikipedia page, it seems that the term "stripe" is coherent with the ext3 man page. I suspect that the confusion is due to the fact that in RAID1 a stripe is in ONE disk (because the others are like parities). In BTRFS the RAID5/6 code uses the structure of RAID1 with some minimal extensions... To be clear, I don't have problem to be adherent to the BTRFS terminology. However I found this very confusing because I was used to a different terminology. I am bit worried about the fact that grub uses both MD/DM code and BTRFS code; a quick look to the code (eg ./grub-core/disk/diskfilter.c) shows that the stripe_size field seems to be related to a disks row without parities. And... yes in BTRFS "chunk" is a completely different beast than what it is reported in the ext3 man page :-) > >> + * >> + * Disk0 Disk1 Disk2 Disk3 >> + * >> + * A1 B1 P1 Q1 >> + * Q2 A2 B2 P2 >> + * P3 Q3 A3 B3 >> + * [...] >> + * >> + * Note that the placement of the parities depends on row index. >> + * In the code below: >> + * - block_nr is the block number without the parities > > Well, it seems to me that the btrfs code introduces confusion not the > spec itself. I would leave code as is but s/block number/stripe number/. Ok I will replace the two terms. However I have to put a warning that this is a "BTRFS" terminology :-) > >> + * (A1 = 0, B1 = 1, A2 = 2, B2 = 3, ...), >> + * - high is the row number (0 for A1...Q1, 1 for Q2...P2, ...), >> + * - stripen is the disk number (0 for A1,Q2,P3, 1 for B1...), > > s/disk number/disk number in a row/ This value doesn't depend by the row. So "number of disk" is more correct > >> + * - off is the logical address to read >> + * - chunk_stripe_length is the size of a block (typically 64k), > > s/a block/a stripe/ > >> + * - nstripes is the number of disks, > > s/number of disks/number of disks in a row/ ditto > > I miss the description of nparities here... Right: + * - nparities is the number of parities (1 for RAID5, 2 for RAID6); + * used only in RAID5/6 code. > >> + * - low is the offset of the data inside a stripe, >> + * - stripe_offset is the disk offset, > > s/the disk offset/the data offset in an array/? Yes > >> + * - csize is the "potential" data to read. It will be reduced to >> + * size if the latter is smaller. >> + */ >> + block_nr = grub_divmod64 (off, chunk_stripe_length, &low); >> + >> + /* >> + * stripen is computed without the parities (0 for A1, A2, A3... >> + * 1 for B1, B2...). >> + */ >> + high = grub_divmod64 (block_nr, nstripes - nparities, &stripen); > > This is clear... > >> + /* >> + * stripen is recomputed considering the parities (0 for A1, 1 for >> + * A2, 2 for A3....). >> + */ >> + grub_divmod64 (high + stripen, nstripes, &stripen); > > ... but this looks strange... You add disk number to row number. Hmmm... > It looks that it works but this is not obvious at first sight. Could you > explain that? What about + /* + * stripen is recomputed considering the parities: different row have + * a different offset, we have to add to stripen the number of row ("high") in + * modulo nstripes (0 for A1, 1 for A2, 2 for A3....). + */ > >> + stripe_offset = low + chunk_stripe_length * high; >> + csize = chunk_stripe_length - low; >> + >> break; >> } >> default: > > Daniel > -- gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 ^ permalink raw reply [flat|nested] 23+ messages in thread
* Re: [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile. 2018-09-26 20:40 ` Goffredo Baroncelli @ 2018-09-27 15:47 ` Daniel Kiper 0 siblings, 0 replies; 23+ messages in thread From: Daniel Kiper @ 2018-09-27 15:47 UTC (permalink / raw) To: kreijack; +Cc: Daniel Kiper, grub-devel, linux-btrfs On Wed, Sep 26, 2018 at 10:40:32PM +0200, Goffredo Baroncelli wrote: > On 25/09/2018 17.31, Daniel Kiper wrote: > > On Wed, Sep 19, 2018 at 08:40:32PM +0200, Goffredo Baroncelli wrote: > >> From: Goffredo Baroncelli <kreijack@inwind.it> > >> > >> Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it> > >> --- > >> grub-core/fs/btrfs.c | 66 ++++++++++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 66 insertions(+) > >> > >> diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c > >> index be195448d..56c42746d 100644 > >> --- a/grub-core/fs/btrfs.c > >> +++ b/grub-core/fs/btrfs.c > >> @@ -119,6 +119,8 @@ struct grub_btrfs_chunk_item > >> #define GRUB_BTRFS_CHUNK_TYPE_RAID1 0x10 > >> #define GRUB_BTRFS_CHUNK_TYPE_DUPLICATED 0x20 > >> #define GRUB_BTRFS_CHUNK_TYPE_RAID10 0x40 > >> +#define GRUB_BTRFS_CHUNK_TYPE_RAID5 0x80 > >> +#define GRUB_BTRFS_CHUNK_TYPE_RAID6 0x100 > >> grub_uint8_t dummy2[0xc]; > >> grub_uint16_t nstripes; > >> grub_uint16_t nsubstripes; > >> @@ -764,6 +766,70 @@ grub_btrfs_read_logical (struct grub_btrfs_data *data, grub_disk_addr_t addr, > >> stripe_offset = low + chunk_stripe_length > >> * high; > >> csize = chunk_stripe_length - low; > >> + break; > >> + } > >> + case GRUB_BTRFS_CHUNK_TYPE_RAID5: > >> + case GRUB_BTRFS_CHUNK_TYPE_RAID6: > >> + { > >> + grub_uint64_t nparities, block_nr, high, low; > >> + > >> + redundancy = 1; /* no redundancy for now */ > >> + > >> + if (grub_le_to_cpu64 (chunk->type) & GRUB_BTRFS_CHUNK_TYPE_RAID5) > >> + { > >> + grub_dprintf ("btrfs", "RAID5\n"); > >> + nparities = 1; > >> + } > >> + else > >> + { > >> + grub_dprintf ("btrfs", "RAID6\n"); > >> + nparities = 2; > >> + } > >> + > >> + /* > >> + * A RAID 6 layout consists of several blocks spread on the disks. > >> + * The raid terminology is used to call all the blocks of a row > >> + * "stripe". Unfortunately the BTRFS terminology confuses block > > > > Stripe is data set or parity (parity stripe) on one disk. Block has > > different meaning. Please stick to btrfs terminology and say it clearly > > in the comment. And even add a link to btrfs wiki page to ease reading. > > > > I think about this one: > > https://btrfs.wiki.kernel.org/index.php/Manpage/mkfs.btrfs#BLOCK_GROUPS.2C_CHUNKS.2C_RAID > > > >> + * and stripe. > > > > I do not think so. Or at least not so much... > > Trust me, generally speaking stripe is the "row" in the disks (without the parity); looking at the ext3 man page: > > .... > stride=stride-size > Configure the filesystem for a RAID array with > stride-size filesystem blocks. This is the number of > blocks read or written to disk before moving to the > next disk, which is sometimes referred to as the > chunk size. This mostly affects placement of > filesystem metadata like bitmaps at mke2fs time to > avoid placing them on a single disk, which can hurt > performance. It may also be used by the block allo??? > cator. > > stripe_width=stripe-width > Configure the filesystem for a RAID array with > stripe-width filesystem blocks per stripe. This is > typically stride-size * N, where N is the number of > data-bearing disks in the RAID (e.g. for RAID 5 > there is one parity disk, so N will be the number of > disks in the array minus 1). This allows the block > allocator to prevent read-modify-write of the parity > in a RAID stripe if possible when the data is writ??? > ten. > > .... > Looking at the RAID5 wikipedia page, it seems that the term "stripe" > is coherent with the ext3 man page. Ugh... It looks that I have messed up things. Sorry about that. > I suspect that the confusion is due to the fact that in RAID1 a stripe > is in ONE disk (because the others are like parities). In BTRFS the > RAID5/6 code uses the structure of RAID1 with some minimal > extensions... > > To be clear, I don't have problem to be adherent to the BTRFS > terminology. However I found this very confusing because I was used to > a different terminology. I am bit worried about the fact that grub Yeah, I have the same feeling. However, I think that in btrfs code we should stay with btrfs terms. Though I think that it make sense to underline differences between btrfs and well known RAID here. > uses both MD/DM code and BTRFS code; a quick look to the code (eg > ./grub-core/disk/diskfilter.c) shows that the stripe_size field seems > to be related to a disks row without parities. > > And... yes in BTRFS "chunk" is a completely different beast than what > it is reported in the ext3 man page :-) As I said above, please say it in the comment. This will ease reading for people who are not used to btrfs terms. > >> + * > >> + * Disk0 Disk1 Disk2 Disk3 > >> + * > >> + * A1 B1 P1 Q1 > >> + * Q2 A2 B2 P2 > >> + * P3 Q3 A3 B3 > >> + * [...] > >> + * > >> + * Note that the placement of the parities depends on row index. > >> + * In the code below: > >> + * - block_nr is the block number without the parities > > > > Well, it seems to me that the btrfs code introduces confusion not the > > spec itself. I would leave code as is but s/block number/stripe number/. > > Ok I will replace the two terms. However I have to put a warning that this is a "BTRFS" terminology :-) Yep, and please explain the differences at the beginning of the comment. > >> + * (A1 = 0, B1 = 1, A2 = 2, B2 = 3, ...), > >> + * - high is the row number (0 for A1...Q1, 1 for Q2...P2, ...), > >> + * - stripen is the disk number (0 for A1,Q2,P3, 1 for B1...), > > > > s/disk number/disk number in a row/ > > This value doesn't depend by the row. So "number of disk" is more correct Yes, but without "row" it is a bit confusing because it suggests that it is an arbitrary number. Even if you give an example next to the description. So, I am insisting on adding "in a row" here. > >> + * - off is the logical address to read > >> + * - chunk_stripe_length is the size of a block (typically 64k), > > > > s/a block/a stripe/ Taking into account discussion above I am not sure right now which one is correct. Please double check and fix it if it is needed. > >> + * - nstripes is the number of disks, > > > > s/number of disks/number of disks in a row/ > ditto As above, Is it total number of disks in array? I do not think so. Hence, I think that "in a row" helps a bit. Even if it is not very precise. However, if you come up with something better I am not against it. > > I miss the description of nparities here... > > Right: > + * - nparities is the number of parities (1 for RAID5, 2 for RAID6); > + * used only in RAID5/6 code. LGTM. > >> + * - low is the offset of the data inside a stripe, > >> + * - stripe_offset is the disk offset, > > > > s/the disk offset/the data offset in an array/? > > Yes > > > > >> + * - csize is the "potential" data to read. It will be reduced to > >> + * size if the latter is smaller. > >> + */ > >> + block_nr = grub_divmod64 (off, chunk_stripe_length, &low); > >> + > >> + /* > >> + * stripen is computed without the parities (0 for A1, A2, A3... > >> + * 1 for B1, B2...). > >> + */ > >> + high = grub_divmod64 (block_nr, nstripes - nparities, &stripen); > > > > This is clear... > > > >> + /* > >> + * stripen is recomputed considering the parities (0 for A1, 1 for > >> + * A2, 2 for A3....). > >> + */ > >> + grub_divmod64 (high + stripen, nstripes, &stripen); > > > > ... but this looks strange... You add disk number to row number. Hmmm... > > It looks that it works but this is not obvious at first sight. Could you > > explain that? > > What about > + /* > + * stripen is recomputed considering the parities: different row have > + * a different offset, we have to add to stripen the number of row ("high") in > + * modulo nstripes (0 for A1, 1 for A2, 2 for A3....). > + */ This is better but not much. You are repeating what code does. I am especially interested in why this math is correct. It is not obvious at first sight. If it is not it should be explained. Otherwise we will forget in a few months why it is correct. Daniel ^ permalink raw reply [flat|nested] 23+ messages in thread
end of thread, other threads:[~2018-10-22 17:30 UTC | newest] Thread overview: 23+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-10-11 18:50 [PATCH V9] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli 2018-10-11 18:50 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli 2018-10-17 13:46 ` Daniel Kiper 2018-10-11 18:50 ` [PATCH 2/9] btrfs: Add helper to check the btrfs header Goffredo Baroncelli 2018-10-11 18:50 ` [PATCH 3/9] btrfs: Move the error logging from find_device() to its caller Goffredo Baroncelli 2018-10-11 18:50 ` [PATCH 4/9] btrfs: Avoid a rescan for a device which was already not found Goffredo Baroncelli 2018-10-17 13:51 ` Daniel Kiper 2018-10-11 18:50 ` [PATCH 5/9] btrfs: Move logging code in grub_btrfs_read_logical() Goffredo Baroncelli 2018-10-11 18:51 ` [PATCH 6/9] btrfs: Refactor the code that read from disk Goffredo Baroncelli 2018-10-11 18:51 ` [PATCH 7/9] btrfs: Add support for recovery for a RAID 5 btrfs profiles Goffredo Baroncelli 2018-10-17 14:14 ` Daniel Kiper 2018-10-11 18:51 ` [PATCH 8/9] btrfs: Make more generic the code for RAID 6 rebuilding Goffredo Baroncelli 2018-10-11 18:51 ` [PATCH 9/9] btrfs: Add RAID 6 recovery for a btrfs filesystem Goffredo Baroncelli 2018-10-17 14:23 ` Daniel Kiper -- strict thread matches above, loose matches on Subject: below -- 2018-10-22 17:29 [PATCH V11] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli 2018-10-22 17:29 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli 2018-10-18 17:55 [PATCH V10] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli 2018-10-18 17:55 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli 2018-09-27 18:34 [PATCH V8] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli 2018-09-27 18:34 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli 2018-10-09 17:51 ` Daniel Kiper 2018-10-11 13:17 ` Daniel Kiper 2018-09-19 18:40 [PATCH V7] Add support for BTRFS raid5/6 to GRUB Goffredo Baroncelli 2018-09-19 18:40 ` [PATCH 1/9] btrfs: Add support for reading a filesystem with a RAID 5 or RAID 6 profile Goffredo Baroncelli 2018-09-25 15:31 ` Daniel Kiper 2018-09-26 20:40 ` Goffredo Baroncelli 2018-09-27 15:47 ` Daniel Kiper
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