[PATCH v5 00/17] xfs: mount API patch series

[PATCH v5 00/17] xfs: mount API patch series

[Ian Kent]

This patch series add support to xfs for the new kernel mount API
as described in the LWN article at https://lwn.net/Articles/780267/.

In the article there's a lengthy description of the reasons for
adopting the API and problems expected to be resolved by using it.

The series has been applied to the repository located at
git://git.kernel.org/pub/scm/fs/xfs/xfs-linux.git, and built and
some simple tests run on it along with the generic xfstests.

Other things that continue to cause me concern:

- Message logging.
  There is error logging done in the VFS by the mount-api code, some
  is VFS specific while some is file system specific. This can lead
  to duplicated and sometimes inconsistent logging.

  The mount-api feature of saving error message text to the mount
  context for later retrieval by fsopen()/fsconfig()/fsmount() users
  is the reason the mount-api log macros are present. But, at the
  moment (last time I looked), these macros will either log the
  error message or save it to the mount context. There's not yet
  a way to modify this behaviour so it which can lead to messages,
  possibly needed for debug purposes, not being sent to the kernel
  log. There's also the pr_xxx() log functions (not a problem for
  xfs AFAICS) that aren't aware of the mount context at all.

  In the xfs patches I've used the same method that is used in
  gfs2 and was suggested by Al Viro (essentially return the error
  if fs_parse() returns one) except that I've also not used the
  mount api log macros to minimise the possibility of lost log
  messages.

  This isn't the best so follow up patches for RFC (with a
  slightly wider audience) will be needed to try and improve
  this aspect of the mount api.

Al Viro has sent a pull request to Linus for the patch containing
get_tree_bdev() and it's included in the current Linus rc tree.
I think there's a small problem with that patch too and I've asked
Al to take a look at it.

So the first two patches in the series are needed only for testing
and these two patches need to be dropped before merging.

Changes for v5:
- give error exit label in xfs_fill_super() a sensible name.
- use original comment about options handling in xfs_fs_remount() for
  comment above xfs_reconfigure().
- use a much simpler comment in xfs_fc_free(), thanks to Brian Foster.
- move cover letter comment about the first two patches above the
  revision comentary so it isn't missed.

Changes for v4:
- changed xfs_fill_super() cleanup back to what it was in v2, until
  I can work out what's causing the problem had previously seen (I can't
  reproduce it myself), since it looks like it was right from the start.
- use get_tree_bdev() instead of vfs_get_block_super() in xfs_get_tree()
  as requested by Al Viro.
- removed redundant initialisation in xfs_fs_fill_super().
- fix long line in xfs_validate_params().
- no need to validate if parameter parsing fails, just return the error.
- summarise reconfigure comment about option handling, transfer bulk
  of comment to commit log message.
- use minimal change in xfs_parse_param(), deffer discussion of mount
  api logging improvements until later and with a wider audience.

Changes for v3:
- fix struct xfs_fs_context initialisation in xfs_parseargs().
- move call to xfs_validate_params() below label "done".
- if allocation of xfs_mount fails return ENOMEM immediately.
- remove erroneous kfree(mp) in xfs_fill_super().
- move the removal of xfs_fs_remount() and xfs_test_remount_options()
  to the switch to mount api patch.
- retain original usage of distinct <option>, no<option> usage.
- fix line length and a white space problem in xfs_parseargs().
- defer introduction of struct fs_context_operations until mount
  api implementation.
- don't use a new line for the void parameter of xfs_mount_alloc().
- check for -ENOPARAM in xfs_parse_param() to report invalid options
  using the options switch (to avoid double entry log messages).
- remove obsolete mount option biosize.
- try and make comment in xfs_fc_free() more understandable.

Changes for v2:
- changed .name to uppercase in fs_parameter_description to ensure
  consistent error log messages between the vfs parser and the xfs
  parameter parser.
- clarify comment above xfs_parse_param() about when possibly
  allocated mp->m_logname or mp->m_rtname are freed.
- factor out xfs_remount_rw() and xfs_remount_ro() from  xfs_remount().
- changed xfs_mount_alloc() to not set super block in xfs_mount so it
  can be re-used when switching to the mount-api.
- fixed don't check for NULL when calling kfree() in xfs_fc_free().
- refactored xfs_parseargs() in an attempt to highlight the code
  that actually changes in converting to use the new mount api.
- dropped xfs-mount-api-rename-xfs_fill_super.patch, it didn't seem
  necessary.
- move comment about remount difficulties above xfs_reconfigure()
  and increase line length to try and make the comment manageable.

---

David Howells (1):
      vfs: Create fs_context-aware mount_bdev() replacement

Ian Kent (16):
      vfs: add missing blkdev_put() in get_tree_bdev()
      xfs: remove very old mount option
      xfs: mount-api - add fs parameter description
      xfs: mount-api - refactor suffix_kstrtoint()
      xfs: mount-api - refactor xfs_parseags()
      xfs: mount-api - make xfs_parse_param() take context .parse_param() args
      xfs: mount-api - move xfs_parseargs() validation to a helper
      xfs: mount-api - refactor xfs_fs_fill_super()
      xfs: mount-api - add xfs_get_tree()
      xfs: mount-api - add xfs_remount_rw() helper
      xfs: mount-api - add xfs_remount_ro() helper
      xfs: mount api - add xfs_reconfigure()
      xfs: mount-api - add xfs_fc_free()
      xfs: mount-api - dont set sb in xfs_mount_alloc()
      xfs: mount-api - switch to new mount-api
      xfs: mount-api - remove remaining legacy mount code


 fs/super.c                 |   97 +++++
 fs/xfs/xfs_super.c         |  926 +++++++++++++++++++++++---------------------
 include/linux/fs_context.h |    5 
 3 files changed, 587 insertions(+), 441 deletions(-)

--
Ian

[PATCH v5 01/17] vfs: Create fs_context-aware mount_bdev() replacement

[Ian Kent]

From: David Howells <dhowells@redhat.com>

Create a function, get_tree_bdev(), that is fs_context-aware and a
->get_tree() counterpart of mount_bdev().

It caches the block device pointer in the fs_context struct so that this
information can be passed into sget_fc()'s test and set functions.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: linux-block@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/super.c                 |   94 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/fs_context.h |    5 ++
 2 files changed, 99 insertions(+)

diff --git a/fs/super.c b/fs/super.c
index 113c58f19425..a7f62c964e58 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1215,6 +1215,7 @@ int get_tree_single(struct fs_context *fc,
 EXPORT_SYMBOL(get_tree_single);
 
 #ifdef CONFIG_BLOCK
+
 static int set_bdev_super(struct super_block *s, void *data)
 {
 	s->s_bdev = data;
@@ -1224,6 +1225,99 @@ static int set_bdev_super(struct super_block *s, void *data)
 	return 0;
 }
 
+static int set_bdev_super_fc(struct super_block *s, struct fs_context *fc)
+{
+	return set_bdev_super(s, fc->sget_key);
+}
+
+static int test_bdev_super_fc(struct super_block *s, struct fs_context *fc)
+{
+	return s->s_bdev == fc->sget_key;
+}
+
+/**
+ * get_tree_bdev - Get a superblock based on a single block device
+ * @fc: The filesystem context holding the parameters
+ * @fill_super: Helper to initialise a new superblock
+ */
+int get_tree_bdev(struct fs_context *fc,
+		int (*fill_super)(struct super_block *,
+				  struct fs_context *))
+{
+	struct block_device *bdev;
+	struct super_block *s;
+	fmode_t mode = FMODE_READ | FMODE_EXCL;
+	int error = 0;
+
+	if (!(fc->sb_flags & SB_RDONLY))
+		mode |= FMODE_WRITE;
+
+	if (!fc->source)
+		return invalf(fc, "No source specified");
+
+	bdev = blkdev_get_by_path(fc->source, mode, fc->fs_type);
+	if (IS_ERR(bdev)) {
+		errorf(fc, "%s: Can't open blockdev", fc->source);
+		return PTR_ERR(bdev);
+	}
+
+	/* Once the superblock is inserted into the list by sget_fc(), s_umount
+	 * will protect the lockfs code from trying to start a snapshot while
+	 * we are mounting
+	 */
+	mutex_lock(&bdev->bd_fsfreeze_mutex);
+	if (bdev->bd_fsfreeze_count > 0) {
+		mutex_unlock(&bdev->bd_fsfreeze_mutex);
+		warnf(fc, "%pg: Can't mount, blockdev is frozen", bdev);
+		return -EBUSY;
+	}
+
+	fc->sb_flags |= SB_NOSEC;
+	fc->sget_key = bdev;
+	s = sget_fc(fc, test_bdev_super_fc, set_bdev_super_fc);
+	mutex_unlock(&bdev->bd_fsfreeze_mutex);
+	if (IS_ERR(s))
+		return PTR_ERR(s);
+
+	if (s->s_root) {
+		/* Don't summarily change the RO/RW state. */
+		if ((fc->sb_flags ^ s->s_flags) & SB_RDONLY) {
+			warnf(fc, "%pg: Can't mount, would change RO state", bdev);
+			deactivate_locked_super(s);
+			blkdev_put(bdev, mode);
+			return -EBUSY;
+		}
+
+		/*
+		 * s_umount nests inside bd_mutex during
+		 * __invalidate_device().  blkdev_put() acquires
+		 * bd_mutex and can't be called under s_umount.  Drop
+		 * s_umount temporarily.  This is safe as we're
+		 * holding an active reference.
+		 */
+		up_write(&s->s_umount);
+		blkdev_put(bdev, mode);
+		down_write(&s->s_umount);
+	} else {
+		s->s_mode = mode;
+		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
+		sb_set_blocksize(s, block_size(bdev));
+		error = fill_super(s, fc);
+		if (error) {
+			deactivate_locked_super(s);
+			return error;
+		}
+
+		s->s_flags |= SB_ACTIVE;
+		bdev->bd_super = s;
+	}
+
+	BUG_ON(fc->root);
+	fc->root = dget(s->s_root);
+	return 0;
+}
+EXPORT_SYMBOL(get_tree_bdev);
+
 static int test_bdev_super(struct super_block *s, void *data)
 {
 	return (void *)s->s_bdev == data;
diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index 7c6fe3d47fa6..7bf6179a83fd 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -88,6 +88,7 @@ struct fs_context {
 	struct mutex		uapi_mutex;	/* Userspace access mutex */
 	struct file_system_type	*fs_type;
 	void			*fs_private;	/* The filesystem's context */
+	void			*sget_key;
 	struct dentry		*root;		/* The root and superblock */
 	struct user_namespace	*user_ns;	/* The user namespace for this mount */
 	struct net		*net_ns;	/* The network namespace for this mount */
@@ -154,6 +155,10 @@ extern int get_tree_single(struct fs_context *fc,
 			 int (*fill_super)(struct super_block *sb,
 					   struct fs_context *fc));
 
+extern int get_tree_bdev(struct fs_context *fc,
+			       int (*fill_super)(struct super_block *sb,
+						 struct fs_context *fc));
+
 extern const struct file_operations fscontext_fops;
 
 /*

[PATCH v5 02/17] vfs: add missing blkdev_put() in get_tree_bdev()

[Ian Kent]

There appear to be a couple of missing blkdev_put() in get_tree_bdev().
---
 fs/super.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/super.c b/fs/super.c
index a7f62c964e58..fd816014bd7d 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1268,6 +1268,7 @@ int get_tree_bdev(struct fs_context *fc,
 	mutex_lock(&bdev->bd_fsfreeze_mutex);
 	if (bdev->bd_fsfreeze_count > 0) {
 		mutex_unlock(&bdev->bd_fsfreeze_mutex);
+		blkdev_put(bdev, mode);
 		warnf(fc, "%pg: Can't mount, blockdev is frozen", bdev);
 		return -EBUSY;
 	}
@@ -1276,8 +1277,10 @@ int get_tree_bdev(struct fs_context *fc,
 	fc->sget_key = bdev;
 	s = sget_fc(fc, test_bdev_super_fc, set_bdev_super_fc);
 	mutex_unlock(&bdev->bd_fsfreeze_mutex);
-	if (IS_ERR(s))
+	if (IS_ERR(s)) {
+		blkdev_put(bdev, mode);
 		return PTR_ERR(s);
+	}
 
 	if (s->s_root) {
 		/* Don't summarily change the RO/RW state. */

[PATCH v5 03/17] xfs: remove very old mount option

[Ian Kent]

It appears the biosize mount option hasn't been documented as
a vilid option since 2005.

So remove it.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index f9450235533c..1010097354a6 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -51,7 +51,7 @@ static struct xfs_kobj xfs_dbg_kobj;	/* global debug sysfs attrs */
  * Table driven mount option parser.
  */
 enum {
-	Opt_logbufs, Opt_logbsize, Opt_logdev, Opt_rtdev, Opt_biosize,
+	Opt_logbufs, Opt_logbsize, Opt_logdev, Opt_rtdev,
 	Opt_wsync, Opt_noalign, Opt_swalloc, Opt_sunit, Opt_swidth, Opt_nouuid,
 	Opt_grpid, Opt_nogrpid, Opt_bsdgroups, Opt_sysvgroups,
 	Opt_allocsize, Opt_norecovery, Opt_inode64, Opt_inode32, Opt_ikeep,
@@ -67,7 +67,6 @@ static const match_table_t tokens = {
 	{Opt_logbsize,	"logbsize=%s"},	/* size of XFS log buffers */
 	{Opt_logdev,	"logdev=%s"},	/* log device */
 	{Opt_rtdev,	"rtdev=%s"},	/* realtime I/O device */
-	{Opt_biosize,	"biosize=%u"},	/* log2 of preferred buffered io size */
 	{Opt_wsync,	"wsync"},	/* safe-mode nfs compatible mount */
 	{Opt_noalign,	"noalign"},	/* turn off stripe alignment */
 	{Opt_swalloc,	"swalloc"},	/* turn on stripe width allocation */
@@ -229,7 +228,6 @@ xfs_parseargs(
 				return -ENOMEM;
 			break;
 		case Opt_allocsize:
-		case Opt_biosize:
 			if (suffix_kstrtoint(args, 10, &iosize))
 				return -EINVAL;
 			iosizelog = ffs(iosize) - 1;

[PATCH v5 04/17] xfs: mount-api - add fs parameter description

[Ian Kent]

The new mount-api uses an array of struct fs_parameter_spec for
parameter parsing, create this table populated with the xfs mount
parameters.

The new mount-api table definition is wider than the token based
parameter table and interleaving the option description comments
between each table line is much less readable than adding them to
the end of each table entry. So add the option description comment
to each entry line even though it causes quite a few of the entries
to be longer than 80 characters.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |   50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 1010097354a6..9c1ce3d70c08 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -38,6 +38,8 @@
 
 #include <linux/magic.h>
 #include <linux/parser.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 
 static const struct super_operations xfs_super_operations;
 struct bio_set xfs_ioend_bioset;
@@ -108,6 +110,54 @@ static const match_table_t tokens = {
 	{Opt_err,	NULL},
 };
 
+static const struct fs_parameter_spec xfs_param_specs[] = {
+ fsparam_u32	("logbufs",    Opt_logbufs),   /* number of XFS log buffers */
+ fsparam_string ("logbsize",   Opt_logbsize),  /* size of XFS log buffers */
+ fsparam_string ("logdev",     Opt_logdev),    /* log device */
+ fsparam_string ("rtdev",      Opt_rtdev),     /* realtime I/O device */
+ fsparam_flag	("wsync",      Opt_wsync),     /* safe-mode nfs compatible mount */
+ fsparam_flag	("noalign",    Opt_noalign),   /* turn off stripe alignment */
+ fsparam_flag	("swalloc",    Opt_swalloc),   /* turn on stripe width allocation */
+ fsparam_u32	("sunit",      Opt_sunit),     /* data volume stripe unit */
+ fsparam_u32	("swidth",     Opt_swidth),    /* data volume stripe width */
+ fsparam_flag	("nouuid",     Opt_nouuid),    /* ignore filesystem UUID */
+ fsparam_flag   ("grpid",      Opt_grpid),     /* group-ID from parent directory */
+ fsparam_flag   ("nogrpid",    Opt_nogrpid),   /* no group-ID from parent directory */
+ fsparam_flag	("bsdgroups",  Opt_bsdgroups), /* group-ID from parent directory */
+ fsparam_flag	("sysvgroups", Opt_sysvgroups),/* group-ID from current process */
+ fsparam_string ("allocsize",  Opt_allocsize), /* preferred allocation size */
+ fsparam_flag	("norecovery", Opt_norecovery),/* don't run XFS recovery */
+ fsparam_flag	("inode64",    Opt_inode64),   /* inodes can be allocated anywhere */
+ fsparam_flag	("inode32",    Opt_inode32),   /* inode allocation limited to XFS_MAXINUMBER_32 */
+ fsparam_flag   ("ikeep",      Opt_ikeep),     /* do not free empty inode clusters */
+ fsparam_flag   ("noikeep",    Opt_noikeep),   /* free empty inode clusters */
+ fsparam_flag   ("largeio",    Opt_largeio),   /* report large I/O sizes in stat() */
+ fsparam_flag   ("nolargeio",  Opt_nolargeio), /* do not report large I/O sizes in stat() */
+ fsparam_flag   ("attr2",      Opt_attr2),     /* do use attr2 attribute format */
+ fsparam_flag   ("noattr2",    Opt_noattr2),   /* do not use attr2 attribute format */
+ fsparam_flag	("filestreams",Opt_filestreams), /* use filestreams allocator */
+ fsparam_flag   ("quota",      Opt_quota),     /* disk quotas (user) */
+ fsparam_flag   ("noquota",    Opt_noquota),   /* no quotas */
+ fsparam_flag	("usrquota",   Opt_usrquota),  /* user quota enabled */
+ fsparam_flag	("grpquota",   Opt_grpquota),  /* group quota enabled */
+ fsparam_flag	("prjquota",   Opt_prjquota),  /* project quota enabled */
+ fsparam_flag	("uquota",     Opt_uquota),    /* user quota (IRIX variant) */
+ fsparam_flag	("gquota",     Opt_gquota),    /* group quota (IRIX variant) */
+ fsparam_flag	("pquota",     Opt_pquota),    /* project quota (IRIX variant) */
+ fsparam_flag	("uqnoenforce",Opt_uqnoenforce), /* user quota limit enforcement */
+ fsparam_flag	("gqnoenforce",Opt_gqnoenforce), /* group quota limit enforcement */
+ fsparam_flag	("pqnoenforce",Opt_pqnoenforce), /* project quota limit enforcement */
+ fsparam_flag	("qnoenforce", Opt_qnoenforce),  /* same as uqnoenforce */
+ fsparam_flag   ("discard",    Opt_discard),   /* Discard unused blocks */
+ fsparam_flag   ("nodiscard",  Opt_nodiscard), /* Do not discard unused blocks */
+ fsparam_flag	("dax",	       Opt_dax),       /* Enable direct access to bdev pages */
+ {}
+};
+
+static const struct fs_parameter_description xfs_fs_parameters = {
+	.name		= "XFS",
+	.specs		= xfs_param_specs,
+};
 
 STATIC int
 suffix_kstrtoint(const substring_t *s, unsigned int base, int *res)

Re: [PATCH v5 04/17] xfs: mount-api - add fs parameter description

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 07:30:31PM +0800, Ian Kent wrote:
> +static const struct fs_parameter_spec xfs_param_specs[] = {
> + fsparam_u32	("logbufs",    Opt_logbufs),   /* number of XFS log buffers */
> + fsparam_string ("logbsize",   Opt_logbsize),  /* size of XFS log buffers */

This has really weird indentation, and a couple overly long lines below.
I'm also not really sure the comments are all that useful here vs in
the actual parser.

Why not:

static const struct fs_parameter_spec xfs_param_specs[] = {
	fsparam_u32("logbufs", Opt_logbufs),
	fsparam_string("logbsize", Opt_logbsize),
	..
};

?

Re: [PATCH v5 04/17] xfs: mount-api - add fs parameter description

[Ian Kent]

Hi Christoph,

On Wed, 2019-10-09 at 07:48 -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 07:30:31PM +0800, Ian Kent wrote:
> > +static const struct fs_parameter_spec xfs_param_specs[] = {
> > + fsparam_u32	("logbufs",    Opt_logbufs),   /* number of XFS
> > log buffers */
> > + fsparam_string ("logbsize",   Opt_logbsize),  /* size of XFS log
> > buffers */
> 
> This has really weird indentation, and a couple overly long lines
> below.
> I'm also not really sure the comments are all that useful here vs in
> the actual parser.
> 
> Why not:
> 
> static const struct fs_parameter_spec xfs_param_specs[] = {
> 	fsparam_u32("logbufs", Opt_logbufs),
> 	fsparam_string("logbsize", Opt_logbsize),
> 	..
> };
> 
> ?

The indentation is purely an effort to preserve the comments.

I originally interleaved them in the structure declaration but
that was even uglier and naturally attracted comments.

I can't remember now if there was a specific request to preserve
the comments.

You suggestion is to add these comments to the case handling in
xfs_parse_param(), correct?

I can do that if there are no other suggestions.

Ian

Re: [PATCH v5 04/17] xfs: mount-api - add fs parameter description

[Christoph Hellwig]

On Thu, Oct 10, 2019 at 08:56:31AM +0800, Ian Kent wrote:
> You suggestion is to add these comments to the case handling in
> xfs_parse_param(), correct?

If there is a strong case for keeping them at all.  Some of them
might be so obvious that we can just drop them I think.

Re: [PATCH v5 04/17] xfs: mount-api - add fs parameter description

[Ian Kent]

On Wed, 2019-10-09 at 23:39 -0700, Christoph Hellwig wrote:
> On Thu, Oct 10, 2019 at 08:56:31AM +0800, Ian Kent wrote:
> > You suggestion is to add these comments to the case handling in
> > xfs_parse_param(), correct?
> 
> If there is a strong case for keeping them at all.  Some of them
> might be so obvious that we can just drop them I think.

I'll try and make sensible judgements when I change it and see
who complains, ;)

Ian

Re: [PATCH v5 04/17] xfs: mount-api - add fs parameter description

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 07:30:31PM +0800, Ian Kent wrote:
> +static const struct fs_parameter_description xfs_fs_parameters = {
> +	.name		= "XFS",
> +	.specs		= xfs_param_specs,
> +};

As this isn't used anywhere it will create a compiler warning and not
bisect cleanly.

[PATCH v5 05/17] xfs: mount-api - refactor suffix_kstrtoint()

[Ian Kent]

The mount-api doesn't have a "human unit" parse type yet so
the options that have values like "10k" etc. still need to
be converted by the fs.

But the value comes to the fs as a string (not a substring_t
type) so there's a need to change the conversion function to
take a character string instead.

After refactoring xfs_parseargs() and changing it to use
xfs_parse_param() match_kstrtoint() will no longer be used
and will be removed.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |   22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 9c1ce3d70c08..6a16750b1314 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -160,13 +160,13 @@ static const struct fs_parameter_description xfs_fs_parameters = {
 };
 
 STATIC int
-suffix_kstrtoint(const substring_t *s, unsigned int base, int *res)
+suffix_kstrtoint(const char *s, unsigned int base, int *res)
 {
 	int	last, shift_left_factor = 0, _res;
 	char	*value;
 	int	ret = 0;
 
-	value = match_strdup(s);
+	value = kstrdup(s, GFP_KERNEL);
 	if (!value)
 		return -ENOMEM;
 
@@ -191,6 +191,20 @@ suffix_kstrtoint(const substring_t *s, unsigned int base, int *res)
 	return ret;
 }
 
+STATIC int
+match_kstrtoint(const substring_t *s, unsigned int base, int *res)
+{
+	const char	*value;
+	int ret;
+
+	value = match_strdup(s);
+	if (!value)
+		return -ENOMEM;
+	ret = suffix_kstrtoint(value, base, res);
+	kfree(value);
+	return ret;
+}
+
 /*
  * This function fills in xfs_mount_t fields based on mount args.
  * Note: the superblock has _not_ yet been read in.
@@ -262,7 +276,7 @@ xfs_parseargs(
 				return -EINVAL;
 			break;
 		case Opt_logbsize:
-			if (suffix_kstrtoint(args, 10, &mp->m_logbsize))
+			if (match_kstrtoint(args, 10, &mp->m_logbsize))
 				return -EINVAL;
 			break;
 		case Opt_logdev:
@@ -278,7 +292,7 @@ xfs_parseargs(
 				return -ENOMEM;
 			break;
 		case Opt_allocsize:
-			if (suffix_kstrtoint(args, 10, &iosize))
+			if (match_kstrtoint(args, 10, &iosize))
 				return -EINVAL;
 			iosizelog = ffs(iosize) - 1;
 			break;

Re: [PATCH v5 05/17] xfs: mount-api - refactor suffix_kstrtoint()

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 07:30:36PM +0800, Ian Kent wrote:
> The mount-api doesn't have a "human unit" parse type yet so
> the options that have values like "10k" etc. still need to
> be converted by the fs.

Any reason you don't lift it to the the core mount api code?

Re: [PATCH v5 05/17] xfs: mount-api - refactor suffix_kstrtoint()

[Al Viro]

On Wed, Oct 09, 2019 at 07:48:59AM -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 07:30:36PM +0800, Ian Kent wrote:
> > The mount-api doesn't have a "human unit" parse type yet so
> > the options that have values like "10k" etc. still need to
> > be converted by the fs.
> 
> Any reason you don't lift it to the the core mount api code?

The garbage enum fs_parameter_type thing.  Once we kill that
(and I *will* kill it), sure - it's a sufficiently common
case to have helpers for it around.  But until then I'll
veto any further additions to that trash pile.

Look at fs_parse() - every sodding value added to that enum
turns into an extra case in a large switch.  It's unsustainable
in that form and I *really* don't want to be in position of
gatekeeper deciding what is and what isn't sufficiently useful
to go there.

What we need to do is to turn fs_parameter_type into a pointer
to function.  With fs_param_is_bool et.al. becoming instances
of such, and fs_parse() switch from hell turning into
	err = p->type(p, param, result);

That won't affect the existing macros or any filesystem code.
If some filesystem wants to have helpers of its own - more
power to it, just use __fsparam(my_bloody_helper, "foo", Opt_foo, 0)
and be done with that.

The thing is, "here's a commonly useful helper, let's take it
to fs/*.c" is much easier than "add a new constant to that
global enum and a case to that ever-growing switch in fs_parser.c".

Re: [PATCH v5 05/17] xfs: mount-api - refactor suffix_kstrtoint()

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 04:21:27PM +0100, Al Viro wrote:
> What we need to do is to turn fs_parameter_type into a pointer
> to function.  With fs_param_is_bool et.al. becoming instances
> of such, and fs_parse() switch from hell turning into
> 	err = p->type(p, param, result);
> 
> That won't affect the existing macros or any filesystem code.
> If some filesystem wants to have helpers of its own - more
> power to it, just use __fsparam(my_bloody_helper, "foo", Opt_foo, 0)
> and be done with that.

Actually, while we could keep the old macros around at least
temporarily for existing users I think killing them actually would
improve the file systems as well.

This:

static const struct fs_parameter_spec afs_param_specs[] = {
	{ "autocell",	Opt_autocell,	fs_parse_flag },
	{ "dyn",	Opt_dyn,	fs_parse_flag },
	{ "flock",	Opt_flock,	fs_parse_enum },
	{ "source",	Opt_source,	fs_parse_string },
        {}
};


is a lot more obvious than:

static const struct fs_parameter_spec afs_param_specs[] = {
        fsparam_flag  ("autocell",      Opt_autocell),
        fsparam_flag  ("dyn",           Opt_dyn),
        fsparam_enum  ("flock",         Opt_flock),
        fsparam_string("source",        Opt_source),
        {}
};

Re: [PATCH v5 05/17] xfs: mount-api - refactor suffix_kstrtoint()

[Al Viro]

On Wed, Oct 09, 2019 at 08:29:11AM -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 04:21:27PM +0100, Al Viro wrote:
> > What we need to do is to turn fs_parameter_type into a pointer
> > to function.  With fs_param_is_bool et.al. becoming instances
> > of such, and fs_parse() switch from hell turning into
> > 	err = p->type(p, param, result);
> > 
> > That won't affect the existing macros or any filesystem code.
> > If some filesystem wants to have helpers of its own - more
> > power to it, just use __fsparam(my_bloody_helper, "foo", Opt_foo, 0)
> > and be done with that.
> 
> Actually, while we could keep the old macros around at least
> temporarily for existing users I think killing them actually would
> improve the file systems as well.
> 
> This:
> 
> static const struct fs_parameter_spec afs_param_specs[] = {
> 	{ "autocell",	Opt_autocell,	fs_parse_flag },
> 	{ "dyn",	Opt_dyn,	fs_parse_flag },
> 	{ "flock",	Opt_flock,	fs_parse_enum },
> 	{ "source",	Opt_source,	fs_parse_string },
>         {}
> };
> 
> 
> is a lot more obvious than:
> 
> static const struct fs_parameter_spec afs_param_specs[] = {
>         fsparam_flag  ("autocell",      Opt_autocell),
>         fsparam_flag  ("dyn",           Opt_dyn),
>         fsparam_enum  ("flock",         Opt_flock),
>         fsparam_string("source",        Opt_source),
>         {}
> };

Except that I want to be able to have something like
-       fsparam_enum   ("errors",             Opt_errors),
+       fsparam_enum   ("errors",             Opt_errors, gfs2_param_errors),
with
+static const struct fs_parameter_enum gfs2_param_errors[] = {
+       {"withdraw",   Opt_errors_withdraw },
+       {"panic",      Opt_errors_panic },
+       {}
+};
instead of having them all squashed into one array, as in
-static const struct fs_parameter_enum gfs2_param_enums[] = {
-       { Opt_quota,    "off",        Opt_quota_off },
-       { Opt_quota,    "account",    Opt_quota_account },
-       { Opt_quota,    "on",         Opt_quota_on },
-       { Opt_data,     "writeback",  Opt_data_writeback },
-       { Opt_data,     "ordered",    Opt_data_ordered },
-       { Opt_errors,   "withdraw",   Opt_errors_withdraw },
-       { Opt_errors,   "panic",      Opt_errors_panic },
...
 const struct fs_parameter_description gfs2_fs_parameters = {
        .name = "gfs2",
        .specs = gfs2_param_specs,
-       .enums = gfs2_param_enums,
 };

IOW, I want to kill ->enums thing.  And ->name is also trivial
to kill, at which point we are left with just what used to be
->specs.

Another thing is, struct fs_parameter_enum becomes pretty
much identical to struct constant_table and can be folded into it.

I have some experiments in that direction (very incomplete right
now) in #work.mount-parser-later; next cycle fodder, I'm afraid.

	Another thing is, consider something like "it's an
integer in range from 2 to 36".  Fairly useful in many cases,
and we could do helpers for that.  Except that they need a pointer
to helper-private data (the limits)...

	These macros somewhat isolate the filesystems until the
things settle down.  And one needs examples of conversions to
see what's missing - inventing a grand scheme out of thin air
doesn't work...

Re: [PATCH v5 05/17] xfs: mount-api - refactor suffix_kstrtoint()

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 05:03:10PM +0100, Al Viro wrote:
> Except that I want to be able to have something like
> -       fsparam_enum   ("errors",             Opt_errors),
> +       fsparam_enum   ("errors",             Opt_errors, gfs2_param_errors),
> with
> +static const struct fs_parameter_enum gfs2_param_errors[] = {
> +       {"withdraw",   Opt_errors_withdraw },
> +       {"panic",      Opt_errors_panic },
> +       {}
> +};
> instead of having them all squashed into one array, as in

Makes total sense and still fits the above scheme.

> IOW, I want to kill ->enums thing.  And ->name is also trivial
> to kill, at which point we are left with just what used to be
> ->specs.

Agreed.

> I have some experiments in that direction (very incomplete right
> now) in #work.mount-parser-later; next cycle fodder, I'm afraid.

I like that a lot, and feel like we really shouldn't do more
conversions until that ground work has been done

Re: [PATCH v5 05/17] xfs: mount-api - refactor suffix_kstrtoint()

[Al Viro]

On Wed, Oct 09, 2019 at 11:01:02AM -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 05:03:10PM +0100, Al Viro wrote:
> > Except that I want to be able to have something like
> > -       fsparam_enum   ("errors",             Opt_errors),
> > +       fsparam_enum   ("errors",             Opt_errors, gfs2_param_errors),
> > with
> > +static const struct fs_parameter_enum gfs2_param_errors[] = {
> > +       {"withdraw",   Opt_errors_withdraw },
> > +       {"panic",      Opt_errors_panic },
> > +       {}
> > +};
> > instead of having them all squashed into one array, as in
> 
> Makes total sense and still fits the above scheme.
> 
> > IOW, I want to kill ->enums thing.  And ->name is also trivial
> > to kill, at which point we are left with just what used to be
> > ->specs.
> 
> Agreed.
> 
> > I have some experiments in that direction (very incomplete right
> > now) in #work.mount-parser-later; next cycle fodder, I'm afraid.
> 
> I like that a lot, and feel like we really shouldn't do more
> conversions until that ground work has been done

I'm not sure - for one thing, it's pretty much orthogonal to the
bulk of conversion; for another, I'm very sceptical about grand
schemes invented out of thin air in hope to cover everything in
the world, without finding out what _is_ there first.

Massaging the parser data structures can be done on top of the
other work just as well - the conflicts will be trivial to deal
with.  And I'm perfectly fine with having the parser stuff
go in last, just prior to -rc1, so resolution will be my
headache.

Alternatively, I can do never-rebased short branch right now,
with the parts of changes likely to cause conflicts, so that
xfs, nfs, etc. work could pull it and be done with that.

Note that e.g. conversion of fs_is_... from enum members to
functions would require zero changes in filesystems.  It would
allow to simplify them later on, but I would very much prefer
to do those extra helpers with converted codebase already
on hand.

Re: [PATCH v5 05/17] xfs: mount-api - refactor suffix_kstrtoint()

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 07:22:22PM +0100, Al Viro wrote:
> Massaging the parser data structures can be done on top of the
> other work just as well - the conflicts will be trivial to deal
> with.  And I'm perfectly fine with having the parser stuff
> go in last, just prior to -rc1, so resolution will be my
> headache.

So, it is that time of the cycle now.  Would you mind updating
the branch and feeding it to Linus?

Re: [PATCH v5 05/17] xfs: mount-api - refactor suffix_kstrtoint()

[Ian Kent]

On Wed, 2019-10-09 at 07:48 -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 07:30:36PM +0800, Ian Kent wrote:
> > The mount-api doesn't have a "human unit" parse type yet so
> > the options that have values like "10k" etc. still need to
> > be converted by the fs.
> 
> Any reason you don't lift it to the the core mount api code?

I talked to David about that and there were some patches but
I didn't see them posted.

But it seems there may have been a reason for that, based on
Al's comments.

I'll leave this as it is for now.

Ian

[PATCH v5 06/17] xfs: mount-api - refactor xfs_parseags()

[Ian Kent]

Refactor xfs_parseags(), move the entire token case block to a
separate function in an attempt to highlight the code that
actually changes in converting to use the new mount api.

The only changes are what's needed to communicate the variables
dsunit, dswidth and iosizelog back to xfs_parseags().

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |  290 ++++++++++++++++++++++++++++------------------------
 1 file changed, 155 insertions(+), 135 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 6a16750b1314..b04aebab69ab 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -205,6 +205,156 @@ match_kstrtoint(const substring_t *s, unsigned int base, int *res)
 	return ret;
 }
 
+STATIC int
+xfs_parse_param(
+	int			token,
+	char			*p,
+	substring_t		*args,
+	struct xfs_mount	*mp,
+	int			*dsunit,
+	int			*dswidth,
+	uint8_t			*iosizelog)
+{
+	int			iosize = 0;
+
+	switch (token) {
+	case Opt_logbufs:
+		if (match_int(args, &mp->m_logbufs))
+			return -EINVAL;
+		break;
+	case Opt_logbsize:
+		if (match_kstrtoint(args, 10, &mp->m_logbsize))
+			return -EINVAL;
+		break;
+	case Opt_logdev:
+		kfree(mp->m_logname);
+		mp->m_logname = match_strdup(args);
+		if (!mp->m_logname)
+			return -ENOMEM;
+		break;
+	case Opt_rtdev:
+		kfree(mp->m_rtname);
+		mp->m_rtname = match_strdup(args);
+		if (!mp->m_rtname)
+			return -ENOMEM;
+		break;
+	case Opt_allocsize:
+		if (match_kstrtoint(args, 10, &iosize))
+			return -EINVAL;
+		*iosizelog = ffs(iosize) - 1;
+		break;
+	case Opt_grpid:
+	case Opt_bsdgroups:
+		mp->m_flags |= XFS_MOUNT_GRPID;
+		break;
+	case Opt_nogrpid:
+	case Opt_sysvgroups:
+		mp->m_flags &= ~XFS_MOUNT_GRPID;
+		break;
+	case Opt_wsync:
+		mp->m_flags |= XFS_MOUNT_WSYNC;
+		break;
+	case Opt_norecovery:
+		mp->m_flags |= XFS_MOUNT_NORECOVERY;
+		break;
+	case Opt_noalign:
+		mp->m_flags |= XFS_MOUNT_NOALIGN;
+		break;
+	case Opt_swalloc:
+		mp->m_flags |= XFS_MOUNT_SWALLOC;
+		break;
+	case Opt_sunit:
+		if (match_int(args, dsunit))
+			return -EINVAL;
+		break;
+	case Opt_swidth:
+		if (match_int(args, dswidth))
+			return -EINVAL;
+		break;
+	case Opt_inode32:
+		mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
+		break;
+	case Opt_inode64:
+		mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
+		break;
+	case Opt_nouuid:
+		mp->m_flags |= XFS_MOUNT_NOUUID;
+		break;
+	case Opt_ikeep:
+		mp->m_flags |= XFS_MOUNT_IKEEP;
+		break;
+	case Opt_noikeep:
+		mp->m_flags &= ~XFS_MOUNT_IKEEP;
+		break;
+	case Opt_largeio:
+		mp->m_flags &= ~XFS_MOUNT_COMPAT_IOSIZE;
+		break;
+	case Opt_nolargeio:
+		mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
+		break;
+	case Opt_attr2:
+		mp->m_flags |= XFS_MOUNT_ATTR2;
+		break;
+	case Opt_noattr2:
+		mp->m_flags &= ~XFS_MOUNT_ATTR2;
+		mp->m_flags |= XFS_MOUNT_NOATTR2;
+		break;
+	case Opt_filestreams:
+		mp->m_flags |= XFS_MOUNT_FILESTREAMS;
+		break;
+	case Opt_noquota:
+		mp->m_qflags &= ~XFS_ALL_QUOTA_ACCT;
+		mp->m_qflags &= ~XFS_ALL_QUOTA_ENFD;
+		mp->m_qflags &= ~XFS_ALL_QUOTA_ACTIVE;
+		break;
+	case Opt_quota:
+	case Opt_uquota:
+	case Opt_usrquota:
+		mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE |
+				 XFS_UQUOTA_ENFD);
+		break;
+	case Opt_qnoenforce:
+	case Opt_uqnoenforce:
+		mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE);
+		mp->m_qflags &= ~XFS_UQUOTA_ENFD;
+		break;
+	case Opt_pquota:
+	case Opt_prjquota:
+		mp->m_qflags |= (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE |
+				 XFS_PQUOTA_ENFD);
+		break;
+	case Opt_pqnoenforce:
+		mp->m_qflags |= (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE);
+		mp->m_qflags &= ~XFS_PQUOTA_ENFD;
+		break;
+	case Opt_gquota:
+	case Opt_grpquota:
+		mp->m_qflags |= (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE |
+				 XFS_GQUOTA_ENFD);
+		break;
+	case Opt_gqnoenforce:
+		mp->m_qflags |= (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE);
+		mp->m_qflags &= ~XFS_GQUOTA_ENFD;
+		break;
+	case Opt_discard:
+		mp->m_flags |= XFS_MOUNT_DISCARD;
+		break;
+	case Opt_nodiscard:
+		mp->m_flags &= ~XFS_MOUNT_DISCARD;
+		break;
+#ifdef CONFIG_FS_DAX
+	case Opt_dax:
+		mp->m_flags |= XFS_MOUNT_DAX;
+		break;
+#endif
+	default:
+		xfs_warn(mp, "unknown mount option [%s].", p);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 /*
  * This function fills in xfs_mount_t fields based on mount args.
  * Note: the superblock has _not_ yet been read in.
@@ -226,7 +376,6 @@ xfs_parseargs(
 	substring_t		args[MAX_OPT_ARGS];
 	int			dsunit = 0;
 	int			dswidth = 0;
-	int			iosize = 0;
 	uint8_t			iosizelog = 0;
 
 	/*
@@ -265,145 +414,16 @@ xfs_parseargs(
 
 	while ((p = strsep(&options, ",")) != NULL) {
 		int		token;
+		int		ret;
 
 		if (!*p)
 			continue;
 
 		token = match_token(p, tokens, args);
-		switch (token) {
-		case Opt_logbufs:
-			if (match_int(args, &mp->m_logbufs))
-				return -EINVAL;
-			break;
-		case Opt_logbsize:
-			if (match_kstrtoint(args, 10, &mp->m_logbsize))
-				return -EINVAL;
-			break;
-		case Opt_logdev:
-			kfree(mp->m_logname);
-			mp->m_logname = match_strdup(args);
-			if (!mp->m_logname)
-				return -ENOMEM;
-			break;
-		case Opt_rtdev:
-			kfree(mp->m_rtname);
-			mp->m_rtname = match_strdup(args);
-			if (!mp->m_rtname)
-				return -ENOMEM;
-			break;
-		case Opt_allocsize:
-			if (match_kstrtoint(args, 10, &iosize))
-				return -EINVAL;
-			iosizelog = ffs(iosize) - 1;
-			break;
-		case Opt_grpid:
-		case Opt_bsdgroups:
-			mp->m_flags |= XFS_MOUNT_GRPID;
-			break;
-		case Opt_nogrpid:
-		case Opt_sysvgroups:
-			mp->m_flags &= ~XFS_MOUNT_GRPID;
-			break;
-		case Opt_wsync:
-			mp->m_flags |= XFS_MOUNT_WSYNC;
-			break;
-		case Opt_norecovery:
-			mp->m_flags |= XFS_MOUNT_NORECOVERY;
-			break;
-		case Opt_noalign:
-			mp->m_flags |= XFS_MOUNT_NOALIGN;
-			break;
-		case Opt_swalloc:
-			mp->m_flags |= XFS_MOUNT_SWALLOC;
-			break;
-		case Opt_sunit:
-			if (match_int(args, &dsunit))
-				return -EINVAL;
-			break;
-		case Opt_swidth:
-			if (match_int(args, &dswidth))
-				return -EINVAL;
-			break;
-		case Opt_inode32:
-			mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
-			break;
-		case Opt_inode64:
-			mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
-			break;
-		case Opt_nouuid:
-			mp->m_flags |= XFS_MOUNT_NOUUID;
-			break;
-		case Opt_ikeep:
-			mp->m_flags |= XFS_MOUNT_IKEEP;
-			break;
-		case Opt_noikeep:
-			mp->m_flags &= ~XFS_MOUNT_IKEEP;
-			break;
-		case Opt_largeio:
-			mp->m_flags &= ~XFS_MOUNT_COMPAT_IOSIZE;
-			break;
-		case Opt_nolargeio:
-			mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
-			break;
-		case Opt_attr2:
-			mp->m_flags |= XFS_MOUNT_ATTR2;
-			break;
-		case Opt_noattr2:
-			mp->m_flags &= ~XFS_MOUNT_ATTR2;
-			mp->m_flags |= XFS_MOUNT_NOATTR2;
-			break;
-		case Opt_filestreams:
-			mp->m_flags |= XFS_MOUNT_FILESTREAMS;
-			break;
-		case Opt_noquota:
-			mp->m_qflags &= ~XFS_ALL_QUOTA_ACCT;
-			mp->m_qflags &= ~XFS_ALL_QUOTA_ENFD;
-			mp->m_qflags &= ~XFS_ALL_QUOTA_ACTIVE;
-			break;
-		case Opt_quota:
-		case Opt_uquota:
-		case Opt_usrquota:
-			mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE |
-					 XFS_UQUOTA_ENFD);
-			break;
-		case Opt_qnoenforce:
-		case Opt_uqnoenforce:
-			mp->m_qflags |= (XFS_UQUOTA_ACCT | XFS_UQUOTA_ACTIVE);
-			mp->m_qflags &= ~XFS_UQUOTA_ENFD;
-			break;
-		case Opt_pquota:
-		case Opt_prjquota:
-			mp->m_qflags |= (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE |
-					 XFS_PQUOTA_ENFD);
-			break;
-		case Opt_pqnoenforce:
-			mp->m_qflags |= (XFS_PQUOTA_ACCT | XFS_PQUOTA_ACTIVE);
-			mp->m_qflags &= ~XFS_PQUOTA_ENFD;
-			break;
-		case Opt_gquota:
-		case Opt_grpquota:
-			mp->m_qflags |= (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE |
-					 XFS_GQUOTA_ENFD);
-			break;
-		case Opt_gqnoenforce:
-			mp->m_qflags |= (XFS_GQUOTA_ACCT | XFS_GQUOTA_ACTIVE);
-			mp->m_qflags &= ~XFS_GQUOTA_ENFD;
-			break;
-		case Opt_discard:
-			mp->m_flags |= XFS_MOUNT_DISCARD;
-			break;
-		case Opt_nodiscard:
-			mp->m_flags &= ~XFS_MOUNT_DISCARD;
-			break;
-#ifdef CONFIG_FS_DAX
-		case Opt_dax:
-			mp->m_flags |= XFS_MOUNT_DAX;
-			break;
-#endif
-		default:
-			xfs_warn(mp, "unknown mount option [%s].", p);
-			return -EINVAL;
-		}
+		ret = xfs_parse_param(token, p, args, mp,
+				      &dsunit, &dswidth, &iosizelog);
+		if (ret)
+			return ret;
 	}
 
 	/*

Re: [PATCH v5 06/17] xfs: mount-api - refactor xfs_parseags()

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 07:30:42PM +0800, Ian Kent wrote:
> Refactor xfs_parseags(), move the entire token case block to a
> separate function in an attempt to highlight the code that
> actually changes in converting to use the new mount api.
> 
> The only changes are what's needed to communicate the variables
> dsunit, dswidth and iosizelog back to xfs_parseags().

I think with just a little refactoring we can communicate those
through the mount structure, where we eventually asign them.  That
will just need a little extra code to clear m_dalign and m_swidth
in the XFS_MOUNT_NOALIGN case.

> +#ifdef CONFIG_FS_DAX
> +	case Opt_dax:
> +		mp->m_flags |= XFS_MOUNT_DAX;
> +		break;
> +#endif

This can be cleaned up a bit using IS_ENABLED().

Re: [PATCH v5 06/17] xfs: mount-api - refactor xfs_parseags()

[Ian Kent]

On Wed, 2019-10-09 at 07:56 -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 07:30:42PM +0800, Ian Kent wrote:
> > Refactor xfs_parseags(), move the entire token case block to a
> > separate function in an attempt to highlight the code that
> > actually changes in converting to use the new mount api.
> > 
> > The only changes are what's needed to communicate the variables
> > dsunit, dswidth and iosizelog back to xfs_parseags().
> 
> I think with just a little refactoring we can communicate those
> through the mount structure, where we eventually asign them.  That
> will just need a little extra code to clear m_dalign and m_swidth
> in the XFS_MOUNT_NOALIGN case.

Ok, I'll have a go at that.

> 
> > +#ifdef CONFIG_FS_DAX
> > +	case Opt_dax:
> > +		mp->m_flags |= XFS_MOUNT_DAX;
> > +		break;
> > +#endif
> 
> This can be cleaned up a bit using IS_ENABLED().

Right, I'll have a look at that.

Ian

[PATCH v5 07/17] xfs: mount-api - make xfs_parse_param() take context .parse_param() args

[Ian Kent]

Make xfs_parse_param() take arguments of the fs context operation
.parse_param() in preparation for switching to use the file system
mount context for mount.

The function fc_parse() only uses the file system context (fc here)
when calling log macros warnf() and invalf() which in turn check
only the fc->log field to determine if the message should be saved
to a context buffer (for later retrival by userspace) or logged
using printk().

In xfs_parse_param() immediately returning an error if fs_parse()
returns one will lead to an inconsistent log entry for unknown
parameters.

But there's also a need to support saving error messages to the
mount context when the fsxxx() system calls are used for passing
options and performing the mount which needs to be done without
possibly losing log entries. This isn't the way that the VFS mount
api log macros work now so follow up patches will be needed later
and they will need to be discussed to work out how this should
acheived for xfs.

Also the temporary function match_kstrtoint() is now unused, remove it.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |  128 +++++++++++++++++++++++++++++-----------------------
 1 file changed, 72 insertions(+), 56 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index b04aebab69ab..7fd3975d5523 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -191,57 +191,51 @@ suffix_kstrtoint(const char *s, unsigned int base, int *res)
 	return ret;
 }
 
-STATIC int
-match_kstrtoint(const substring_t *s, unsigned int base, int *res)
-{
-	const char	*value;
-	int ret;
-
-	value = match_strdup(s);
-	if (!value)
-		return -ENOMEM;
-	ret = suffix_kstrtoint(value, base, res);
-	kfree(value);
-	return ret;
-}
+struct xfs_fs_context {
+	int	dsunit;
+	int	dswidth;
+	uint8_t	iosizelog;
+};
 
 STATIC int
 xfs_parse_param(
-	int			token,
-	char			*p,
-	substring_t		*args,
-	struct xfs_mount	*mp,
-	int			*dsunit,
-	int			*dswidth,
-	uint8_t			*iosizelog)
+	struct fs_context	*fc,
+	struct fs_parameter	*param)
 {
+	struct xfs_fs_context	*ctx = fc->fs_private;
+	struct xfs_mount	*mp = fc->s_fs_info;
+	struct fs_parse_result	result;
 	int			iosize = 0;
+	int			opt;
 
-	switch (token) {
+	opt = fs_parse(fc, &xfs_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
 	case Opt_logbufs:
-		if (match_int(args, &mp->m_logbufs))
-			return -EINVAL;
+		mp->m_logbufs = result.uint_32;
 		break;
 	case Opt_logbsize:
-		if (match_kstrtoint(args, 10, &mp->m_logbsize))
+		if (suffix_kstrtoint(param->string, 10, &mp->m_logbsize))
 			return -EINVAL;
 		break;
 	case Opt_logdev:
 		kfree(mp->m_logname);
-		mp->m_logname = match_strdup(args);
+		mp->m_logname = kstrdup(param->string, GFP_KERNEL);
 		if (!mp->m_logname)
 			return -ENOMEM;
 		break;
 	case Opt_rtdev:
 		kfree(mp->m_rtname);
-		mp->m_rtname = match_strdup(args);
+		mp->m_rtname = kstrdup(param->string, GFP_KERNEL);
 		if (!mp->m_rtname)
 			return -ENOMEM;
 		break;
 	case Opt_allocsize:
-		if (match_kstrtoint(args, 10, &iosize))
+		if (suffix_kstrtoint(param->string, 10, &iosize))
 			return -EINVAL;
-		*iosizelog = ffs(iosize) - 1;
+		ctx->iosizelog = ffs(iosize) - 1;
 		break;
 	case Opt_grpid:
 	case Opt_bsdgroups:
@@ -264,12 +258,10 @@ xfs_parse_param(
 		mp->m_flags |= XFS_MOUNT_SWALLOC;
 		break;
 	case Opt_sunit:
-		if (match_int(args, dsunit))
-			return -EINVAL;
+		ctx->dsunit = result.uint_32;
 		break;
 	case Opt_swidth:
-		if (match_int(args, dswidth))
-			return -EINVAL;
+		ctx->dswidth = result.uint_32;
 		break;
 	case Opt_inode32:
 		mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
@@ -348,7 +340,7 @@ xfs_parse_param(
 		break;
 #endif
 	default:
-		xfs_warn(mp, "unknown mount option [%s].", p);
+		xfs_warn(mp, "unknown mount option [%s].", param->key);
 		return -EINVAL;
 	}
 
@@ -373,10 +365,16 @@ xfs_parseargs(
 {
 	const struct super_block *sb = mp->m_super;
 	char			*p;
-	substring_t		args[MAX_OPT_ARGS];
-	int			dsunit = 0;
-	int			dswidth = 0;
-	uint8_t			iosizelog = 0;
+	struct fs_context	fc;
+	struct xfs_fs_context	context;
+	struct xfs_fs_context	*ctx;
+	int			ret;
+
+	memset(&fc, 0, sizeof(fc));
+	memset(&context, 0, sizeof(context));
+	fc.fs_private = &context;
+	ctx = &context;
+	fc.s_fs_info = mp;
 
 	/*
 	 * set up the mount name first so all the errors will refer to the
@@ -413,16 +411,33 @@ xfs_parseargs(
 		goto done;
 
 	while ((p = strsep(&options, ",")) != NULL) {
-		int		token;
-		int		ret;
+		struct fs_parameter	param;
+		char			*value;
 
 		if (!*p)
 			continue;
 
-		token = match_token(p, tokens, args);
-		ret = xfs_parse_param(token, p, args, mp,
-				      &dsunit, &dswidth, &iosizelog);
-		if (ret)
+		param.key = p;
+		param.type = fs_value_is_string;
+		param.string = NULL;
+		param.size = 0;
+
+		value = strchr(p, '=');
+		if (value) {
+			*value++ = 0;
+			param.size = strlen(value);
+			if (param.size > 0) {
+				param.string = kmemdup_nul(value,
+							   param.size,
+							   GFP_KERNEL);
+				if (!param.string)
+					return -ENOMEM;
+			}
+		}
+
+		ret = xfs_parse_param(&fc, &param);
+		kfree(param.string);
+		if (ret < 0)
 			return ret;
 	}
 
@@ -435,7 +450,8 @@ xfs_parseargs(
 		return -EINVAL;
 	}
 
-	if ((mp->m_flags & XFS_MOUNT_NOALIGN) && (dsunit || dswidth)) {
+	if ((mp->m_flags & XFS_MOUNT_NOALIGN) &&
+	    (ctx->dsunit || ctx->dswidth)) {
 		xfs_warn(mp,
 	"sunit and swidth options incompatible with the noalign option");
 		return -EINVAL;
@@ -448,28 +464,28 @@ xfs_parseargs(
 	}
 #endif
 
-	if ((dsunit && !dswidth) || (!dsunit && dswidth)) {
+	if ((ctx->dsunit && !ctx->dswidth) || (!ctx->dsunit && ctx->dswidth)) {
 		xfs_warn(mp, "sunit and swidth must be specified together");
 		return -EINVAL;
 	}
 
-	if (dsunit && (dswidth % dsunit != 0)) {
+	if (ctx->dsunit && (ctx->dswidth % ctx->dsunit != 0)) {
 		xfs_warn(mp,
 	"stripe width (%d) must be a multiple of the stripe unit (%d)",
-			dswidth, dsunit);
+			ctx->dswidth, ctx->dsunit);
 		return -EINVAL;
 	}
 
 done:
-	if (dsunit && !(mp->m_flags & XFS_MOUNT_NOALIGN)) {
+	if (ctx->dsunit && !(mp->m_flags & XFS_MOUNT_NOALIGN)) {
 		/*
 		 * At this point the superblock has not been read
 		 * in, therefore we do not know the block size.
 		 * Before the mount call ends we will convert
 		 * these to FSBs.
 		 */
-		mp->m_dalign = dsunit;
-		mp->m_swidth = dswidth;
+		mp->m_dalign = ctx->dsunit;
+		mp->m_swidth = ctx->dswidth;
 	}
 
 	if (mp->m_logbufs != -1 &&
@@ -491,18 +507,18 @@ xfs_parseargs(
 		return -EINVAL;
 	}
 
-	if (iosizelog) {
-		if (iosizelog > XFS_MAX_IO_LOG ||
-		    iosizelog < XFS_MIN_IO_LOG) {
+	if (ctx->iosizelog) {
+		if (ctx->iosizelog > XFS_MAX_IO_LOG ||
+		    ctx->iosizelog < XFS_MIN_IO_LOG) {
 			xfs_warn(mp, "invalid log iosize: %d [not %d-%d]",
-				iosizelog, XFS_MIN_IO_LOG,
+				ctx->iosizelog, XFS_MIN_IO_LOG,
 				XFS_MAX_IO_LOG);
 			return -EINVAL;
 		}
 
 		mp->m_flags |= XFS_MOUNT_DFLT_IOSIZE;
-		mp->m_readio_log = iosizelog;
-		mp->m_writeio_log = iosizelog;
+		mp->m_readio_log = ctx->iosizelog;
+		mp->m_writeio_log = ctx->iosizelog;
 	}
 
 	return 0;

[PATCH v5 08/17] xfs: mount-api - move xfs_parseargs() validation to a helper

[Ian Kent]

Move the validation code of xfs_parseargs() into a helper for later
use within the mount context methods.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |  147 +++++++++++++++++++++++++++++++++-------------------
 1 file changed, 94 insertions(+), 53 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 7fd3975d5523..7008355df065 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -347,6 +347,98 @@ xfs_parse_param(
 	return 0;
 }
 
+STATIC int
+xfs_validate_params(
+	struct xfs_mount        *mp,
+	struct xfs_fs_context   *ctx,
+	bool			nooptions)
+{
+	if (nooptions)
+		goto noopts;
+
+	/*
+	 * no recovery flag requires a read-only mount
+	 */
+	if ((mp->m_flags & XFS_MOUNT_NORECOVERY) &&
+	    !(mp->m_flags & XFS_MOUNT_RDONLY)) {
+		xfs_warn(mp, "no-recovery mounts must be read-only.");
+		return -EINVAL;
+	}
+
+	if ((mp->m_flags & XFS_MOUNT_NOALIGN) &&
+	    (ctx->dsunit || ctx->dswidth)) {
+		xfs_warn(mp,
+	"sunit and swidth options incompatible with the noalign option");
+		return -EINVAL;
+	}
+
+#ifndef CONFIG_XFS_QUOTA
+	if (XFS_IS_QUOTA_RUNNING(mp)) {
+		xfs_warn(mp, "quota support not available in this kernel.");
+		return -EINVAL;
+	}
+#endif
+
+	if ((ctx->dsunit && !ctx->dswidth) || (!ctx->dsunit && ctx->dswidth)) {
+		xfs_warn(mp, "sunit and swidth must be specified together");
+		return -EINVAL;
+	}
+
+	if (ctx->dsunit && (ctx->dswidth % ctx->dsunit != 0)) {
+		xfs_warn(mp,
+	"stripe width (%d) must be a multiple of the stripe unit (%d)",
+			ctx->dswidth, ctx->dsunit);
+		return -EINVAL;
+	}
+
+noopts:
+	if (ctx->dsunit && !(mp->m_flags & XFS_MOUNT_NOALIGN)) {
+		/*
+		 * At this point the superblock has not been read
+		 * in, therefore we do not know the block size.
+		 * Before the mount call ends we will convert
+		 * these to FSBs.
+		 */
+		mp->m_dalign = ctx->dsunit;
+		mp->m_swidth = ctx->dswidth;
+	}
+
+	if (mp->m_logbufs != -1 &&
+	    mp->m_logbufs != 0 &&
+	    (mp->m_logbufs < XLOG_MIN_ICLOGS ||
+	     mp->m_logbufs > XLOG_MAX_ICLOGS)) {
+		xfs_warn(mp, "invalid logbufs value: %d [not %d-%d]",
+			mp->m_logbufs, XLOG_MIN_ICLOGS, XLOG_MAX_ICLOGS);
+		return -EINVAL;
+	}
+	if (mp->m_logbsize != -1 &&
+	    mp->m_logbsize !=  0 &&
+	    (mp->m_logbsize < XLOG_MIN_RECORD_BSIZE ||
+	     mp->m_logbsize > XLOG_MAX_RECORD_BSIZE ||
+	     !is_power_of_2(mp->m_logbsize))) {
+		xfs_warn(mp,
+			"invalid logbufsize: %d [not 16k,32k,64k,128k or 256k]",
+			mp->m_logbsize);
+		return -EINVAL;
+	}
+
+	if (ctx->iosizelog) {
+		if (ctx->iosizelog > XFS_MAX_IO_LOG ||
+		    ctx->iosizelog < XFS_MIN_IO_LOG) {
+			xfs_warn(mp, "invalid log iosize: %d [not %d-%d]",
+				ctx->iosizelog, XFS_MIN_IO_LOG,
+				XFS_MAX_IO_LOG);
+			return -EINVAL;
+		}
+
+		mp->m_flags |= XFS_MOUNT_DFLT_IOSIZE;
+		mp->m_readio_log = ctx->iosizelog;
+		mp->m_writeio_log = ctx->iosizelog;
+	}
+
+	return 0;
+}
+
 /*
  * This function fills in xfs_mount_t fields based on mount args.
  * Note: the superblock has _not_ yet been read in.
@@ -441,15 +533,6 @@ xfs_parseargs(
 			return ret;
 	}
 
-	/*
-	 * no recovery flag requires a read-only mount
-	 */
-	if ((mp->m_flags & XFS_MOUNT_NORECOVERY) &&
-	    !(mp->m_flags & XFS_MOUNT_RDONLY)) {
-		xfs_warn(mp, "no-recovery mounts must be read-only.");
-		return -EINVAL;
-	}
-
 	if ((mp->m_flags & XFS_MOUNT_NOALIGN) &&
 	    (ctx->dsunit || ctx->dswidth)) {
 		xfs_warn(mp,
@@ -477,51 +560,9 @@ xfs_parseargs(
 	}
 
 done:
-	if (ctx->dsunit && !(mp->m_flags & XFS_MOUNT_NOALIGN)) {
-		/*
-		 * At this point the superblock has not been read
-		 * in, therefore we do not know the block size.
-		 * Before the mount call ends we will convert
-		 * these to FSBs.
-		 */
-		mp->m_dalign = ctx->dsunit;
-		mp->m_swidth = ctx->dswidth;
-	}
+	ret = xfs_validate_params(mp, &context, false);
 
-	if (mp->m_logbufs != -1 &&
-	    mp->m_logbufs != 0 &&
-	    (mp->m_logbufs < XLOG_MIN_ICLOGS ||
-	     mp->m_logbufs > XLOG_MAX_ICLOGS)) {
-		xfs_warn(mp, "invalid logbufs value: %d [not %d-%d]",
-			mp->m_logbufs, XLOG_MIN_ICLOGS, XLOG_MAX_ICLOGS);
-		return -EINVAL;
-	}
-	if (mp->m_logbsize != -1 &&
-	    mp->m_logbsize !=  0 &&
-	    (mp->m_logbsize < XLOG_MIN_RECORD_BSIZE ||
-	     mp->m_logbsize > XLOG_MAX_RECORD_BSIZE ||
-	     !is_power_of_2(mp->m_logbsize))) {
-		xfs_warn(mp,
-			"invalid logbufsize: %d [not 16k,32k,64k,128k or 256k]",
-			mp->m_logbsize);
-		return -EINVAL;
-	}
-
-	if (ctx->iosizelog) {
-		if (ctx->iosizelog > XFS_MAX_IO_LOG ||
-		    ctx->iosizelog < XFS_MIN_IO_LOG) {
-			xfs_warn(mp, "invalid log iosize: %d [not %d-%d]",
-				ctx->iosizelog, XFS_MIN_IO_LOG,
-				XFS_MAX_IO_LOG);
-			return -EINVAL;
-		}
-
-		mp->m_flags |= XFS_MOUNT_DFLT_IOSIZE;
-		mp->m_readio_log = ctx->iosizelog;
-		mp->m_writeio_log = ctx->iosizelog;
-	}
-
-	return 0;
+	return ret;
 }
 
 struct proc_xfs_info {

Re: [PATCH v5 08/17] xfs: mount-api - move xfs_parseargs() validation to a helper

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 07:30:52PM +0800, Ian Kent wrote:
> +#ifndef CONFIG_XFS_QUOTA
> +	if (XFS_IS_QUOTA_RUNNING(mp)) {
> +		xfs_warn(mp, "quota support not available in this kernel.");
> +		return -EINVAL;
> +	}
> +#endif

this can use IS_ENABLED.

Re: [PATCH v5 08/17] xfs: mount-api - move xfs_parseargs() validation to a helper

[Darrick J. Wong]

On Wed, Oct 09, 2019 at 08:02:06AM -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 07:30:52PM +0800, Ian Kent wrote:
> > +#ifndef CONFIG_XFS_QUOTA
> > +	if (XFS_IS_QUOTA_RUNNING(mp)) {
> > +		xfs_warn(mp, "quota support not available in this kernel.");
> > +		return -EINVAL;
> > +	}
> > +#endif
> 
> this can use IS_ENABLED.

I didn't think that macro needed a CONFIG_XFS_QUOTA check...?

--D

Re: [PATCH v5 08/17] xfs: mount-api - move xfs_parseargs() validation to a helper

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 12:47:47PM -0700, Darrick J. Wong wrote:
> On Wed, Oct 09, 2019 at 08:02:06AM -0700, Christoph Hellwig wrote:
> > On Wed, Oct 09, 2019 at 07:30:52PM +0800, Ian Kent wrote:
> > > +#ifndef CONFIG_XFS_QUOTA
> > > +	if (XFS_IS_QUOTA_RUNNING(mp)) {
> > > +		xfs_warn(mp, "quota support not available in this kernel.");
> > > +		return -EINVAL;
> > > +	}
> > > +#endif
> > 
> > this can use IS_ENABLED.
> 
> I didn't think that macro needed a CONFIG_XFS_QUOTA check...?

Even better if we don't need anything at al..

Re: [PATCH v5 08/17] xfs: mount-api - move xfs_parseargs() validation to a helper

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 11:38:24PM -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 12:47:47PM -0700, Darrick J. Wong wrote:
> > On Wed, Oct 09, 2019 at 08:02:06AM -0700, Christoph Hellwig wrote:
> > > On Wed, Oct 09, 2019 at 07:30:52PM +0800, Ian Kent wrote:
> > > > +#ifndef CONFIG_XFS_QUOTA
> > > > +	if (XFS_IS_QUOTA_RUNNING(mp)) {
> > > > +		xfs_warn(mp, "quota support not available in this kernel.");
> > > > +		return -EINVAL;
> > > > +	}
> > > > +#endif
> > > 
> > > this can use IS_ENABLED.
> > 
> > I didn't think that macro needed a CONFIG_XFS_QUOTA check...?
> 
> Even better if we don't need anything at al..

Actually.  The test is and #ifndef, so yes we ctually need the check.
That being said I think and opencoded m_qflags != 0 instead of
XFS_IS_QUOTA_RUNNING would actually describing the intent to the
reader as we directly manipulate m_qflags elsewhere in the mount
code.

[PATCH v5 09/17] xfs: mount-api - refactor xfs_fs_fill_super()

[Ian Kent]

Much of the code in xfs_fs_fill_super() will be used by the fill super
function of the new mount-api.

So refactor the common code into a helper in an attempt to show what's
actually changed.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |   64 +++++++++++++++++++++++++++++++++-------------------
 1 file changed, 41 insertions(+), 23 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 7008355df065..cc2da9093e34 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1712,27 +1712,14 @@ xfs_mount_alloc(
 
 
 STATIC int
-xfs_fs_fill_super(
-	struct super_block	*sb,
-	void			*data,
+__xfs_fs_fill_super(
+	struct xfs_mount	*mp,
 	int			silent)
 {
+	struct super_block	*sb = mp->m_super;
 	struct inode		*root;
-	struct xfs_mount	*mp = NULL;
-	int			flags = 0, error = -ENOMEM;
-
-	/*
-	 * allocate mp and do all low-level struct initializations before we
-	 * attach it to the super
-	 */
-	mp = xfs_mount_alloc(sb);
-	if (!mp)
-		goto out;
-	sb->s_fs_info = mp;
-
-	error = xfs_parseargs(mp, (char *)data);
-	if (error)
-		goto out_free_fsname;
+	int			flags = 0;
+	int			error;
 
 	sb_min_blocksize(sb, BBSIZE);
 	sb->s_xattr = xfs_xattr_handlers;
@@ -1759,7 +1746,7 @@ xfs_fs_fill_super(
 
 	error = xfs_open_devices(mp);
 	if (error)
-		goto out_free_fsname;
+		goto out;
 
 	error = xfs_init_mount_workqueues(mp);
 	if (error)
@@ -1894,10 +1881,6 @@ xfs_fs_fill_super(
 	xfs_destroy_mount_workqueues(mp);
  out_close_devices:
 	xfs_close_devices(mp);
- out_free_fsname:
-	sb->s_fs_info = NULL;
-	xfs_free_fsname(mp);
-	kfree(mp);
  out:
 	return error;
 
@@ -1907,6 +1890,41 @@ xfs_fs_fill_super(
 	goto out_free_sb;
 }
 
+STATIC int
+xfs_fs_fill_super(
+	struct super_block	*sb,
+	void			*data,
+	int			silent)
+{
+	struct xfs_mount	*mp;
+	int			error;
+
+	/*
+	 * allocate mp and do all low-level struct initializations before we
+	 * attach it to the super
+	 */
+	mp = xfs_mount_alloc(sb);
+	if (!mp)
+		return -ENOMEM;
+	sb->s_fs_info = mp;
+
+	error = xfs_parseargs(mp, (char *)data);
+	if (error)
+		goto out_free_fsname;
+
+	error = __xfs_fs_fill_super(mp, silent);
+	if (error)
+		goto out_free_fsname;
+
+	return 0;
+
+ out_free_fsname:
+	sb->s_fs_info = NULL;
+	xfs_free_fsname(mp);
+	kfree(mp);
+	return error;
+}
+
 STATIC void
 xfs_fs_put_super(
 	struct super_block	*sb)

Re: [PATCH v5 09/17] xfs: mount-api - refactor xfs_fs_fill_super()

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 07:30:58PM +0800, Ian Kent wrote:
> Much of the code in xfs_fs_fill_super() will be used by the fill super
> function of the new mount-api.
> 
> So refactor the common code into a helper in an attempt to show what's
> actually changed.

I hate how this ends up leaving a pointless helper around.  If you
really absolutely want to add the helper here please also remove it
again at the end of the series.

Re: [PATCH v5 09/17] xfs: mount-api - refactor xfs_fs_fill_super()

[Ian Kent]

On Wed, 2019-10-09 at 08:03 -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 07:30:58PM +0800, Ian Kent wrote:
> > Much of the code in xfs_fs_fill_super() will be used by the fill
> > super
> > function of the new mount-api.
> > 
> > So refactor the common code into a helper in an attempt to show
> > what's
> > actually changed.
> 
> I hate how this ends up leaving a pointless helper around.  If you
> really absolutely want to add the helper here please also remove it
> again at the end of the series.

I think I do want to retain the helper.
Merging it back in afterwards is fine too, I'll do that.

Ian

[PATCH v5 10/17] xfs: mount-api - add xfs_get_tree()

[Ian Kent]

Add the fs_context_operations method .get_tree that validates
mount options and fills the super block as previously done
by the file_system_type .mount method.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |   50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index cc2da9093e34..314acafffd0b 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1925,6 +1925,51 @@ xfs_fs_fill_super(
 	return error;
 }
 
+STATIC int
+xfs_fill_super(
+	struct super_block	*sb,
+	struct fs_context	*fc)
+{
+	struct xfs_fs_context	*ctx = fc->fs_private;
+	struct xfs_mount	*mp = sb->s_fs_info;
+	int			silent = fc->sb_flags & SB_SILENT;
+	int			error = -ENOMEM;
+
+	mp->m_super = sb;
+
+	/*
+	 * set up the mount name first so all the errors will refer to the
+	 * correct device.
+	 */
+	mp->m_fsname = kstrndup(sb->s_id, MAXNAMELEN, GFP_KERNEL);
+	if (!mp->m_fsname)
+		goto out_error;
+	mp->m_fsname_len = strlen(mp->m_fsname) + 1;
+
+	error = xfs_validate_params(mp, ctx, false);
+	if (error)
+		goto out_error;
+
+	error = __xfs_fs_fill_super(mp, silent);
+	if (error)
+		goto out_error;
+
+	return 0;
+
+ out_error:
+	sb->s_fs_info = NULL;
+	xfs_free_fsname(mp);
+	kfree(mp);
+	return error;
+}
+
+STATIC int
+xfs_get_tree(
+	struct fs_context	*fc)
+{
+	return get_tree_bdev(fc, xfs_fill_super);
+}
+
 STATIC void
 xfs_fs_put_super(
 	struct super_block	*sb)
@@ -1995,6 +2040,11 @@ static const struct super_operations xfs_super_operations = {
 	.free_cached_objects	= xfs_fs_free_cached_objects,
 };
 
+static const struct fs_context_operations xfs_context_ops = {
+	.parse_param = xfs_parse_param,
+	.get_tree    = xfs_get_tree,
+};
+
 static struct file_system_type xfs_fs_type = {
 	.owner			= THIS_MODULE,
 	.name			= "xfs",

Re: [PATCH v5 10/17] xfs: mount-api - add xfs_get_tree()

[Christoph Hellwig]

> +	/*
> +	 * set up the mount name first so all the errors will refer to the
> +	 * correct device.
> +	 */
> +	mp->m_fsname = kstrndup(sb->s_id, MAXNAMELEN, GFP_KERNEL);
> +	if (!mp->m_fsname)
> +		goto out_error;
> +	mp->m_fsname_len = strlen(mp->m_fsname) + 1;

m_fsname_len is entirelt unused.  m_fsname just has a few users, so
maybe in a prep patch just kill both of them and use sb->s_id instead.

Re: [PATCH v5 10/17] xfs: mount-api - add xfs_get_tree()

[Ian Kent]

On Wed, 2019-10-09 at 08:04 -0700, Christoph Hellwig wrote:
> > +	/*
> > +	 * set up the mount name first so all the errors will refer to
> > the
> > +	 * correct device.
> > +	 */
> > +	mp->m_fsname = kstrndup(sb->s_id, MAXNAMELEN, GFP_KERNEL);
> > +	if (!mp->m_fsname)
> > +		goto out_error;
> > +	mp->m_fsname_len = strlen(mp->m_fsname) + 1;
> 
> m_fsname_len is entirelt unused.  m_fsname just has a few users, so
> maybe in a prep patch just kill both of them and use sb->s_id
> instead.

Ok, I'll also have a look at doing that.

Ian

[PATCH v5 11/17] xfs: mount-api - add xfs_remount_rw() helper

[Ian Kent]

Factor the remount read write code into a helper to simplify the
subsequent change from the super block method .remount_fs to the
mount-api fs_context_operations method .reconfigure.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |  115 +++++++++++++++++++++++++++++-----------------------
 1 file changed, 64 insertions(+), 51 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 314acafffd0b..94996d1a8c0f 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1363,6 +1363,68 @@ xfs_test_remount_options(
 	return error;
 }
 
+STATIC int
+xfs_remount_rw(
+	struct xfs_mount	*mp)
+{
+	xfs_sb_t		*sbp = &mp->m_sb;
+	int error;
+
+	if (mp->m_flags & XFS_MOUNT_NORECOVERY) {
+		xfs_warn(mp,
+			"ro->rw transition prohibited on norecovery mount");
+		return -EINVAL;
+	}
+
+	if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
+	    xfs_sb_has_ro_compat_feature(sbp, XFS_SB_FEAT_RO_COMPAT_UNKNOWN)) {
+		xfs_warn(mp,
+	"ro->rw transition prohibited on unknown (0x%x) ro-compat filesystem",
+			(sbp->sb_features_ro_compat &
+				XFS_SB_FEAT_RO_COMPAT_UNKNOWN));
+		return -EINVAL;
+	}
+
+	mp->m_flags &= ~XFS_MOUNT_RDONLY;
+
+	/*
+	 * If this is the first remount to writeable state we
+	 * might have some superblock changes to update.
+	 */
+	if (mp->m_update_sb) {
+		error = xfs_sync_sb(mp, false);
+		if (error) {
+			xfs_warn(mp, "failed to write sb changes");
+			return error;
+		}
+		mp->m_update_sb = false;
+	}
+
+	/*
+	 * Fill out the reserve pool if it is empty. Use the stashed
+	 * value if it is non-zero, otherwise go with the default.
+	 */
+	xfs_restore_resvblks(mp);
+	xfs_log_work_queue(mp);
+
+	/* Recover any CoW blocks that never got remapped. */
+	error = xfs_reflink_recover_cow(mp);
+	if (error) {
+		xfs_err(mp,
+			"Error %d recovering leftover CoW allocations.", error);
+			xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+		return error;
+	}
+	xfs_start_block_reaping(mp);
+
+	/* Create the per-AG metadata reservation pool .*/
+	error = xfs_fs_reserve_ag_blocks(mp);
+	if (error && error != -ENOSPC)
+		return error;
+
+	return 0;
+}
+
 STATIC int
 xfs_fs_remount(
 	struct super_block	*sb,
@@ -1426,57 +1488,8 @@ xfs_fs_remount(
 
 	/* ro -> rw */
 	if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(*flags & SB_RDONLY)) {
-		if (mp->m_flags & XFS_MOUNT_NORECOVERY) {
-			xfs_warn(mp,
-		"ro->rw transition prohibited on norecovery mount");
-			return -EINVAL;
-		}
-
-		if (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
-		    xfs_sb_has_ro_compat_feature(sbp,
-					XFS_SB_FEAT_RO_COMPAT_UNKNOWN)) {
-			xfs_warn(mp,
-"ro->rw transition prohibited on unknown (0x%x) ro-compat filesystem",
-				(sbp->sb_features_ro_compat &
-					XFS_SB_FEAT_RO_COMPAT_UNKNOWN));
-			return -EINVAL;
-		}
-
-		mp->m_flags &= ~XFS_MOUNT_RDONLY;
-
-		/*
-		 * If this is the first remount to writeable state we
-		 * might have some superblock changes to update.
-		 */
-		if (mp->m_update_sb) {
-			error = xfs_sync_sb(mp, false);
-			if (error) {
-				xfs_warn(mp, "failed to write sb changes");
-				return error;
-			}
-			mp->m_update_sb = false;
-		}
-
-		/*
-		 * Fill out the reserve pool if it is empty. Use the stashed
-		 * value if it is non-zero, otherwise go with the default.
-		 */
-		xfs_restore_resvblks(mp);
-		xfs_log_work_queue(mp);
-
-		/* Recover any CoW blocks that never got remapped. */
-		error = xfs_reflink_recover_cow(mp);
-		if (error) {
-			xfs_err(mp,
-	"Error %d recovering leftover CoW allocations.", error);
-			xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
-			return error;
-		}
-		xfs_start_block_reaping(mp);
-
-		/* Create the per-AG metadata reservation pool .*/
-		error = xfs_fs_reserve_ag_blocks(mp);
-		if (error && error != -ENOSPC)
+		error = xfs_remount_rw(mp);
+		if (error)
 			return error;
 	}
 

[PATCH v5 12/17] xfs: mount-api - add xfs_remount_ro() helper

[Ian Kent]

Factor the remount read only code into a helper to simplify the
subsequent change from the super block method .remount_fs to the
mount-api fs_context_operations method .reconfigure.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |   73 +++++++++++++++++++++++++++++++---------------------
 1 file changed, 43 insertions(+), 30 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 94996d1a8c0f..7e634706626b 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1425,6 +1425,47 @@ xfs_remount_rw(
 	return 0;
 }
 
+STATIC int
+xfs_remount_ro(
+	struct xfs_mount	*mp)
+{
+	int error;
+
+	/*
+	 * Cancel background eofb scanning so it cannot race with the
+	 * final log force+buftarg wait and deadlock the remount.
+	 */
+	xfs_stop_block_reaping(mp);
+
+	/* Get rid of any leftover CoW reservations... */
+	error = xfs_icache_free_cowblocks(mp, NULL);
+	if (error) {
+		xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+		return error;
+	}
+
+	/* Free the per-AG metadata reservation pool. */
+	error = xfs_fs_unreserve_ag_blocks(mp);
+	if (error) {
+		xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+		return error;
+	}
+
+	/*
+	 * Before we sync the metadata, we need to free up the reserve
+	 * block pool so that the used block count in the superblock on
+	 * disk is correct at the end of the remount. Stash the current
+	 * reserve pool size so that if we get remounted rw, we can
+	 * return it to the same size.
+	 */
+	xfs_save_resvblks(mp);
+
+	xfs_quiesce_attr(mp);
+	mp->m_flags |= XFS_MOUNT_RDONLY;
+
+	return 0;
+}
+
 STATIC int
 xfs_fs_remount(
 	struct super_block	*sb,
@@ -1495,37 +1536,9 @@ xfs_fs_remount(
 
 	/* rw -> ro */
 	if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (*flags & SB_RDONLY)) {
-		/*
-		 * Cancel background eofb scanning so it cannot race with the
-		 * final log force+buftarg wait and deadlock the remount.
-		 */
-		xfs_stop_block_reaping(mp);
-
-		/* Get rid of any leftover CoW reservations... */
-		error = xfs_icache_free_cowblocks(mp, NULL);
-		if (error) {
-			xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
-			return error;
-		}
-
-		/* Free the per-AG metadata reservation pool. */
-		error = xfs_fs_unreserve_ag_blocks(mp);
-		if (error) {
-			xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+		error = xfs_remount_ro(mp);
+		if (error)
 			return error;
-		}
-
-		/*
-		 * Before we sync the metadata, we need to free up the reserve
-		 * block pool so that the used block count in the superblock on
-		 * disk is correct at the end of the remount. Stash the current
-		 * reserve pool size so that if we get remounted rw, we can
-		 * return it to the same size.
-		 */
-		xfs_save_resvblks(mp);
-
-		xfs_quiesce_attr(mp);
-		mp->m_flags |= XFS_MOUNT_RDONLY;
 	}
 
 	return 0;

[PATCH v5 13/17] xfs: mount api - add xfs_reconfigure()

[Ian Kent]

Add the fs_context_operations method .reconfigure that performs
remount validation as previously done by the super_operations
.remount_fs method.

Signed-off-by: Ian Kent <raven@themaw.net>
---
 fs/xfs/xfs_super.c |   62 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 7e634706626b..230b0e2a184c 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1544,6 +1544,67 @@ xfs_fs_remount(
 	return 0;
 }
 
+/*
+ * Logically we would return an error here to prevent users
+ * from believing they might have changed mount options using
+ * remount which can't be changed.
+ *
+ * But unfortunately mount(8) adds all options from mtab and
+ * fstab to the mount arguments in some cases so we can't
+ * blindly reject options, but have to check for each specified
+ * option if it actually differs from the currently set option
+ * and only reject it if that's the case.
+ *
+ * Until that is implemented we return success for every remount
+ * request, and silently ignore all options that we can't actually
+ * change.
+ */
+STATIC int
+xfs_reconfigure(
+	struct fs_context *fc)
+{
+	struct xfs_fs_context	*ctx = fc->fs_private;
+	struct xfs_mount	*mp = XFS_M(fc->root->d_sb);
+	struct xfs_mount        *new_mp = fc->s_fs_info;
+	xfs_sb_t		*sbp = &mp->m_sb;
+	int			flags = fc->sb_flags;
+	int			error;
+
+	error = xfs_validate_params(new_mp, ctx, false);
+	if (error)
+		return error;
+
+	/* inode32 -> inode64 */
+	if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) &&
+	    !(new_mp->m_flags & XFS_MOUNT_SMALL_INUMS)) {
+		mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
+		mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
+	}
+
+	/* inode64 -> inode32 */
+	if (!(mp->m_flags & XFS_MOUNT_SMALL_INUMS) &&
+	    (new_mp->m_flags & XFS_MOUNT_SMALL_INUMS)) {
+		mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
+		mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
+	}
+
+	/* ro -> rw */
+	if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(flags & SB_RDONLY)) {
+		error = xfs_remount_rw(mp);
+		if (error)
+			return error;
+	}
+
+	/* rw -> ro */
+	if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (flags & SB_RDONLY)) {
+		error = xfs_remount_ro(mp);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
+
 /*
  * Second stage of a freeze. The data is already frozen so we only
  * need to take care of the metadata. Once that's done sync the superblock
@@ -2069,6 +2130,7 @@ static const struct super_operations xfs_super_operations = {
 static const struct fs_context_operations xfs_context_ops = {
 	.parse_param = xfs_parse_param,
 	.get_tree    = xfs_get_tree,
+	.reconfigure = xfs_reconfigure,
 };
 
 static struct file_system_type xfs_fs_type = {

Re: [PATCH v5 13/17] xfs: mount api - add xfs_reconfigure()

[Brian Foster]

On Wed, Oct 09, 2019 at 07:31:19PM +0800, Ian Kent wrote:
> Add the fs_context_operations method .reconfigure that performs
> remount validation as previously done by the super_operations
> .remount_fs method.
> 
> Signed-off-by: Ian Kent <raven@themaw.net>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/xfs_super.c |   62 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 62 insertions(+)
> 
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 7e634706626b..230b0e2a184c 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -1544,6 +1544,67 @@ xfs_fs_remount(
>  	return 0;
>  }
>  
> +/*
> + * Logically we would return an error here to prevent users
> + * from believing they might have changed mount options using
> + * remount which can't be changed.
> + *
> + * But unfortunately mount(8) adds all options from mtab and
> + * fstab to the mount arguments in some cases so we can't
> + * blindly reject options, but have to check for each specified
> + * option if it actually differs from the currently set option
> + * and only reject it if that's the case.
> + *
> + * Until that is implemented we return success for every remount
> + * request, and silently ignore all options that we can't actually
> + * change.
> + */
> +STATIC int
> +xfs_reconfigure(
> +	struct fs_context *fc)
> +{
> +	struct xfs_fs_context	*ctx = fc->fs_private;
> +	struct xfs_mount	*mp = XFS_M(fc->root->d_sb);
> +	struct xfs_mount        *new_mp = fc->s_fs_info;
> +	xfs_sb_t		*sbp = &mp->m_sb;
> +	int			flags = fc->sb_flags;
> +	int			error;
> +
> +	error = xfs_validate_params(new_mp, ctx, false);
> +	if (error)
> +		return error;
> +
> +	/* inode32 -> inode64 */
> +	if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) &&
> +	    !(new_mp->m_flags & XFS_MOUNT_SMALL_INUMS)) {
> +		mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
> +		mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
> +	}
> +
> +	/* inode64 -> inode32 */
> +	if (!(mp->m_flags & XFS_MOUNT_SMALL_INUMS) &&
> +	    (new_mp->m_flags & XFS_MOUNT_SMALL_INUMS)) {
> +		mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
> +		mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
> +	}
> +
> +	/* ro -> rw */
> +	if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(flags & SB_RDONLY)) {
> +		error = xfs_remount_rw(mp);
> +		if (error)
> +			return error;
> +	}
> +
> +	/* rw -> ro */
> +	if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (flags & SB_RDONLY)) {
> +		error = xfs_remount_ro(mp);
> +		if (error)
> +			return error;
> +	}
> +
> +	return 0;
> +}
> +
>  /*
>   * Second stage of a freeze. The data is already frozen so we only
>   * need to take care of the metadata. Once that's done sync the superblock
> @@ -2069,6 +2130,7 @@ static const struct super_operations xfs_super_operations = {
>  static const struct fs_context_operations xfs_context_ops = {
>  	.parse_param = xfs_parse_param,
>  	.get_tree    = xfs_get_tree,
> +	.reconfigure = xfs_reconfigure,
>  };
>  
>  static struct file_system_type xfs_fs_type = {
> 

Re: [PATCH v5 13/17] xfs: mount api - add xfs_reconfigure()

[Christoph Hellwig]

> +/*
> + * Logically we would return an error here to prevent users
> + * from believing they might have changed mount options using
> + * remount which can't be changed.
> + *
> + * But unfortunately mount(8) adds all options from mtab and
> + * fstab to the mount arguments in some cases so we can't
> + * blindly reject options, but have to check for each specified
> + * option if it actually differs from the currently set option
> + * and only reject it if that's the case.
> + *
> + * Until that is implemented we return success for every remount
> + * request, and silently ignore all options that we can't actually
> + * change.
> + */

Please use up all 80 chars available for your comments.

Re: [PATCH v5 13/17] xfs: mount api - add xfs_reconfigure()

[Ian Kent]

On Wed, 2019-10-09 at 08:05 -0700, Christoph Hellwig wrote:
> > +/*
> > + * Logically we would return an error here to prevent users
> > + * from believing they might have changed mount options using
> > + * remount which can't be changed.
> > + *
> > + * But unfortunately mount(8) adds all options from mtab and
> > + * fstab to the mount arguments in some cases so we can't
> > + * blindly reject options, but have to check for each specified
> > + * option if it actually differs from the currently set option
> > + * and only reject it if that's the case.
> > + *
> > + * Until that is implemented we return success for every remount
> > + * request, and silently ignore all options that we can't actually
> > + * change.
> > + */
> 
> Please use up all 80 chars available for your comments.

Will do.

Ian

[PATCH v5 14/17] xfs: mount-api - add xfs_fc_free()

[Ian Kent]

Add the fs_context_operations method .free that performs fs
context cleanup on context release.

Signed-off-by: Ian Kent <raven@themaw.net>
---
 fs/xfs/xfs_super.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 230b0e2a184c..c7c33395b648 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -2127,10 +2127,29 @@ static const struct super_operations xfs_super_operations = {
 	.free_cached_objects	= xfs_fs_free_cached_objects,
 };
 
+static void xfs_fc_free(struct fs_context *fc)
+{
+	struct xfs_fs_context	*ctx = fc->fs_private;
+	struct xfs_mount	*mp = fc->s_fs_info;
+
+	/*
+	 * mp and ctx are stored in the fs_context when it is
+	 * initialized. mp is transferred to the superblock on
+	 * a successful mount, but if an error occurs before the
+	 * transfer we have to free it here.
+	 */
+	if (mp) {
+		xfs_free_fsname(mp);
+		kfree(mp);
+	}
+	kfree(ctx);
+}
+
 static const struct fs_context_operations xfs_context_ops = {
 	.parse_param = xfs_parse_param,
 	.get_tree    = xfs_get_tree,
 	.reconfigure = xfs_reconfigure,
+	.free        = xfs_fc_free,
 };
 
 static struct file_system_type xfs_fs_type = {

Re: [PATCH v5 14/17] xfs: mount-api - add xfs_fc_free()

[Brian Foster]

On Wed, Oct 09, 2019 at 07:31:24PM +0800, Ian Kent wrote:
> Add the fs_context_operations method .free that performs fs
> context cleanup on context release.
> 
> Signed-off-by: Ian Kent <raven@themaw.net>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/xfs_super.c |   19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 230b0e2a184c..c7c33395b648 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -2127,10 +2127,29 @@ static const struct super_operations xfs_super_operations = {
>  	.free_cached_objects	= xfs_fs_free_cached_objects,
>  };
>  
> +static void xfs_fc_free(struct fs_context *fc)
> +{
> +	struct xfs_fs_context	*ctx = fc->fs_private;
> +	struct xfs_mount	*mp = fc->s_fs_info;
> +
> +	/*
> +	 * mp and ctx are stored in the fs_context when it is
> +	 * initialized. mp is transferred to the superblock on
> +	 * a successful mount, but if an error occurs before the
> +	 * transfer we have to free it here.
> +	 */
> +	if (mp) {
> +		xfs_free_fsname(mp);
> +		kfree(mp);
> +	}
> +	kfree(ctx);
> +}
> +
>  static const struct fs_context_operations xfs_context_ops = {
>  	.parse_param = xfs_parse_param,
>  	.get_tree    = xfs_get_tree,
>  	.reconfigure = xfs_reconfigure,
> +	.free        = xfs_fc_free,
>  };
>  
>  static struct file_system_type xfs_fs_type = {
> 

[PATCH v5 15/17] xfs: mount-api - dont set sb in xfs_mount_alloc()

[Ian Kent]

When changing to use the new mount api the super block won't be
available when the xfs_mount info struct is allocated so move
setting the super block in xfs_mount to xfs_fs_fill_super().

Also change xfs_mount_alloc() decalaration static -> STATIC.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index c7c33395b648..910739789aed 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1766,9 +1766,8 @@ xfs_destroy_percpu_counters(
 	percpu_counter_destroy(&mp->m_delalloc_blks);
 }
 
-static struct xfs_mount *
-xfs_mount_alloc(
-	struct super_block	*sb)
+STATIC struct xfs_mount *
+xfs_mount_alloc(void)
 {
 	struct xfs_mount	*mp;
 
@@ -1776,7 +1775,6 @@ xfs_mount_alloc(
 	if (!mp)
 		return NULL;
 
-	mp->m_super = sb;
 	spin_lock_init(&mp->m_sb_lock);
 	spin_lock_init(&mp->m_agirotor_lock);
 	INIT_RADIX_TREE(&mp->m_perag_tree, GFP_ATOMIC);
@@ -1990,9 +1988,10 @@ xfs_fs_fill_super(
 	 * allocate mp and do all low-level struct initializations before we
 	 * attach it to the super
 	 */
-	mp = xfs_mount_alloc(sb);
+	mp = xfs_mount_alloc();
 	if (!mp)
 		return -ENOMEM;
+	mp->m_super = sb;
 	sb->s_fs_info = mp;
 
 	error = xfs_parseargs(mp, (char *)data);

[PATCH v5 16/17] xfs: mount-api - switch to new mount-api

[Ian Kent]

The infrastructure needed to use the new mount api is now
in place, switch over to use it.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |  321 ++++++++--------------------------------------------
 1 file changed, 49 insertions(+), 272 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 910739789aed..680dcad3cd1e 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -439,132 +439,6 @@ xfs_validate_params(
 	return 0;
 }
 
-/*
- * This function fills in xfs_mount_t fields based on mount args.
- * Note: the superblock has _not_ yet been read in.
- *
- * Note that this function leaks the various device name allocations on
- * failure.  The caller takes care of them.
- *
- * *sb is const because this is also used to test options on the remount
- * path, and we don't want this to have any side effects at remount time.
- * Today this function does not change *sb, but just to future-proof...
- */
-STATIC int
-xfs_parseargs(
-	struct xfs_mount	*mp,
-	char			*options)
-{
-	const struct super_block *sb = mp->m_super;
-	char			*p;
-	struct fs_context	fc;
-	struct xfs_fs_context	context;
-	struct xfs_fs_context	*ctx;
-	int			ret;
-
-	memset(&fc, 0, sizeof(fc));
-	memset(&context, 0, sizeof(context));
-	fc.fs_private = &context;
-	ctx = &context;
-	fc.s_fs_info = mp;
-
-	/*
-	 * set up the mount name first so all the errors will refer to the
-	 * correct device.
-	 */
-	mp->m_fsname = kstrndup(sb->s_id, MAXNAMELEN, GFP_KERNEL);
-	if (!mp->m_fsname)
-		return -ENOMEM;
-	mp->m_fsname_len = strlen(mp->m_fsname) + 1;
-
-	/*
-	 * Copy binary VFS mount flags we are interested in.
-	 */
-	if (sb_rdonly(sb))
-		mp->m_flags |= XFS_MOUNT_RDONLY;
-	if (sb->s_flags & SB_DIRSYNC)
-		mp->m_flags |= XFS_MOUNT_DIRSYNC;
-	if (sb->s_flags & SB_SYNCHRONOUS)
-		mp->m_flags |= XFS_MOUNT_WSYNC;
-
-	/*
-	 * Set some default flags that could be cleared by the mount option
-	 * parsing.
-	 */
-	mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
-
-	/*
-	 * These can be overridden by the mount option parsing.
-	 */
-	mp->m_logbufs = -1;
-	mp->m_logbsize = -1;
-
-	if (!options)
-		goto done;
-
-	while ((p = strsep(&options, ",")) != NULL) {
-		struct fs_parameter	param;
-		char			*value;
-
-		if (!*p)
-			continue;
-
-		param.key = p;
-		param.type = fs_value_is_string;
-		param.string = NULL;
-		param.size = 0;
-
-		value = strchr(p, '=');
-		if (value) {
-			*value++ = 0;
-			param.size = strlen(value);
-			if (param.size > 0) {
-				param.string = kmemdup_nul(value,
-							   param.size,
-							   GFP_KERNEL);
-				if (!param.string)
-					return -ENOMEM;
-			}
-		}
-
-		ret = xfs_parse_param(&fc, &param);
-		kfree(param.string);
-		if (ret < 0)
-			return ret;
-	}
-
-	if ((mp->m_flags & XFS_MOUNT_NOALIGN) &&
-	    (ctx->dsunit || ctx->dswidth)) {
-		xfs_warn(mp,
-	"sunit and swidth options incompatible with the noalign option");
-		return -EINVAL;
-	}
-
-#ifndef CONFIG_XFS_QUOTA
-	if (XFS_IS_QUOTA_RUNNING(mp)) {
-		xfs_warn(mp, "quota support not available in this kernel.");
-		return -EINVAL;
-	}
-#endif
-
-	if ((ctx->dsunit && !ctx->dswidth) || (!ctx->dsunit && ctx->dswidth)) {
-		xfs_warn(mp, "sunit and swidth must be specified together");
-		return -EINVAL;
-	}
-
-	if (ctx->dsunit && (ctx->dswidth % ctx->dsunit != 0)) {
-		xfs_warn(mp,
-	"stripe width (%d) must be a multiple of the stripe unit (%d)",
-			ctx->dswidth, ctx->dsunit);
-		return -EINVAL;
-	}
-
-done:
-	ret = xfs_validate_params(mp, &context, false);
-
-	return ret;
-}
-
 struct proc_xfs_info {
 	uint64_t	flag;
 	char		*str;
@@ -1343,26 +1217,6 @@ xfs_quiesce_attr(
 	xfs_log_quiesce(mp);
 }
 
-STATIC int
-xfs_test_remount_options(
-	struct super_block	*sb,
-	char			*options)
-{
-	int			error = 0;
-	struct xfs_mount	*tmp_mp;
-
-	tmp_mp = kmem_zalloc(sizeof(*tmp_mp), KM_MAYFAIL);
-	if (!tmp_mp)
-		return -ENOMEM;
-
-	tmp_mp->m_super = sb;
-	error = xfs_parseargs(tmp_mp, options);
-	xfs_free_fsname(tmp_mp);
-	kmem_free(tmp_mp);
-
-	return error;
-}
-
 STATIC int
 xfs_remount_rw(
 	struct xfs_mount	*mp)
@@ -1466,84 +1320,6 @@ xfs_remount_ro(
 	return 0;
 }
 
-STATIC int
-xfs_fs_remount(
-	struct super_block	*sb,
-	int			*flags,
-	char			*options)
-{
-	struct xfs_mount	*mp = XFS_M(sb);
-	xfs_sb_t		*sbp = &mp->m_sb;
-	substring_t		args[MAX_OPT_ARGS];
-	char			*p;
-	int			error;
-
-	/* First, check for complete junk; i.e. invalid options */
-	error = xfs_test_remount_options(sb, options);
-	if (error)
-		return error;
-
-	sync_filesystem(sb);
-	while ((p = strsep(&options, ",")) != NULL) {
-		int token;
-
-		if (!*p)
-			continue;
-
-		token = match_token(p, tokens, args);
-		switch (token) {
-		case Opt_inode64:
-			mp->m_flags &= ~XFS_MOUNT_SMALL_INUMS;
-			mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
-			break;
-		case Opt_inode32:
-			mp->m_flags |= XFS_MOUNT_SMALL_INUMS;
-			mp->m_maxagi = xfs_set_inode_alloc(mp, sbp->sb_agcount);
-			break;
-		default:
-			/*
-			 * Logically we would return an error here to prevent
-			 * users from believing they might have changed
-			 * mount options using remount which can't be changed.
-			 *
-			 * But unfortunately mount(8) adds all options from
-			 * mtab and fstab to the mount arguments in some cases
-			 * so we can't blindly reject options, but have to
-			 * check for each specified option if it actually
-			 * differs from the currently set option and only
-			 * reject it if that's the case.
-			 *
-			 * Until that is implemented we return success for
-			 * every remount request, and silently ignore all
-			 * options that we can't actually change.
-			 */
-#if 0
-			xfs_info(mp,
-		"mount option \"%s\" not supported for remount", p);
-			return -EINVAL;
-#else
-			break;
-#endif
-		}
-	}
-
-	/* ro -> rw */
-	if ((mp->m_flags & XFS_MOUNT_RDONLY) && !(*flags & SB_RDONLY)) {
-		error = xfs_remount_rw(mp);
-		if (error)
-			return error;
-	}
-
-	/* rw -> ro */
-	if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (*flags & SB_RDONLY)) {
-		error = xfs_remount_ro(mp);
-		if (error)
-			return error;
-	}
-
-	return 0;
-}
-
 /*
  * Logically we would return an error here to prevent users
  * from believing they might have changed mount options using
@@ -1975,42 +1751,6 @@ __xfs_fs_fill_super(
 	goto out_free_sb;
 }
 
-STATIC int
-xfs_fs_fill_super(
-	struct super_block	*sb,
-	void			*data,
-	int			silent)
-{
-	struct xfs_mount	*mp;
-	int			error;
-
-	/*
-	 * allocate mp and do all low-level struct initializations before we
-	 * attach it to the super
-	 */
-	mp = xfs_mount_alloc();
-	if (!mp)
-		return -ENOMEM;
-	mp->m_super = sb;
-	sb->s_fs_info = mp;
-
-	error = xfs_parseargs(mp, (char *)data);
-	if (error)
-		goto out_free_fsname;
-
-	error = __xfs_fs_fill_super(mp, silent);
-	if (error)
-		goto out_free_fsname;
-
-	return 0;
-
- out_free_fsname:
-	sb->s_fs_info = NULL;
-	xfs_free_fsname(mp);
-	kfree(mp);
-	return error;
-}
-
 STATIC int
 xfs_fill_super(
 	struct super_block	*sb,
@@ -2081,16 +1821,6 @@ xfs_fs_put_super(
 	kfree(mp);
 }
 
-STATIC struct dentry *
-xfs_fs_mount(
-	struct file_system_type	*fs_type,
-	int			flags,
-	const char		*dev_name,
-	void			*data)
-{
-	return mount_bdev(fs_type, flags, dev_name, data, xfs_fs_fill_super);
-}
-
 static long
 xfs_fs_nr_cached_objects(
 	struct super_block	*sb,
@@ -2120,7 +1850,6 @@ static const struct super_operations xfs_super_operations = {
 	.freeze_fs		= xfs_fs_freeze,
 	.unfreeze_fs		= xfs_fs_unfreeze,
 	.statfs			= xfs_fs_statfs,
-	.remount_fs		= xfs_fs_remount,
 	.show_options		= xfs_fs_show_options,
 	.nr_cached_objects	= xfs_fs_nr_cached_objects,
 	.free_cached_objects	= xfs_fs_free_cached_objects,
@@ -2151,10 +1880,58 @@ static const struct fs_context_operations xfs_context_ops = {
 	.free        = xfs_fc_free,
 };
 
+/*
+ * Set up the filesystem mount context.
+ */
+int xfs_init_fs_context(struct fs_context *fc)
+{
+	struct xfs_fs_context	*ctx;
+	struct xfs_mount	*mp;
+
+	ctx = kzalloc(sizeof(struct xfs_fs_context), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	mp = xfs_mount_alloc();
+	if (!mp) {
+		kfree(ctx);
+		return -ENOMEM;
+	}
+
+	/*
+	 * Set some default flags that could be cleared by the mount option
+	 * parsing.
+	 */
+	mp->m_flags |= XFS_MOUNT_COMPAT_IOSIZE;
+
+	/*
+	 * These can be overridden by the mount option parsing.
+	 */
+	mp->m_logbufs = -1;
+	mp->m_logbsize = -1;
+
+	/*
+	 * Copy binary VFS mount flags we are interested in.
+	 */
+	if (fc->sb_flags & SB_RDONLY)
+		mp->m_flags |= XFS_MOUNT_RDONLY;
+	if (fc->sb_flags & SB_DIRSYNC)
+		mp->m_flags |= XFS_MOUNT_DIRSYNC;
+	if (fc->sb_flags & SB_SYNCHRONOUS)
+		mp->m_flags |= XFS_MOUNT_WSYNC;
+
+	fc->fs_private = ctx;
+	fc->s_fs_info = mp;
+	fc->ops = &xfs_context_ops;
+
+	return 0;
+}
+
 static struct file_system_type xfs_fs_type = {
 	.owner			= THIS_MODULE,
 	.name			= "xfs",
-	.mount			= xfs_fs_mount,
+	.init_fs_context	= xfs_init_fs_context,
+	.parameters		= &xfs_fs_parameters,
 	.kill_sb		= kill_block_super,
 	.fs_flags		= FS_REQUIRES_DEV,
 };

Re: [PATCH v5 16/17] xfs: mount-api - switch to new mount-api

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 07:31:35PM +0800, Ian Kent wrote:
> The infrastructure needed to use the new mount api is now
> in place, switch over to use it.

I find it weird that you add the methods and params table first and
think the series would be a lot easier to understand if you just did
independent refatoring first and then a big switch over.

> +/*
> + * Set up the filesystem mount context.
> + */

Not exactly a very helpful comment, after all it is a method instance..

> +int xfs_init_fs_context(struct fs_context *fc)

This should be static.  Btw, for most of the STATICs in the series we'd
just use static these days as well.  And at least for method instances
STATIC actually never made any sense..

Re: [PATCH v5 16/17] xfs: mount-api - switch to new mount-api

[Ian Kent]

On Wed, 2019-10-09 at 08:10 -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 07:31:35PM +0800, Ian Kent wrote:
> > The infrastructure needed to use the new mount api is now
> > in place, switch over to use it.
> 
> I find it weird that you add the methods and params table first and
> think the series would be a lot easier to understand if you just did
> independent refatoring first and then a big switch over.

That sounds like a good suggestion.
I suspect it'll take a bit effort, I'll have a go at it though.

> 
> > +/*
> > + * Set up the filesystem mount context.
> > + */
> 
> Not exactly a very helpful comment, after all it is a method
> instance..

Yep, I'll remove it.

> 
> > +int xfs_init_fs_context(struct fs_context *fc)
> 
> This should be static.  Btw, for most of the STATICs in the series
> we'd
> just use static these days as well.  And at least for method
> instances
> STATIC actually never made any sense..

Ok, I'll fix that.

Ian

[PATCH v5 17/17] xfs: mount-api - remove remaining legacy mount code

[Ian Kent]

Now that the new mount api is being used the remaining old mount
code can be removed.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_super.c |   48 +-----------------------------------------------
 1 file changed, 1 insertion(+), 47 deletions(-)

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 680dcad3cd1e..f3f204f202c6 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -61,53 +61,7 @@ enum {
 	Opt_filestreams, Opt_quota, Opt_noquota, Opt_usrquota, Opt_grpquota,
 	Opt_prjquota, Opt_uquota, Opt_gquota, Opt_pquota,
 	Opt_uqnoenforce, Opt_gqnoenforce, Opt_pqnoenforce, Opt_qnoenforce,
-	Opt_discard, Opt_nodiscard, Opt_dax, Opt_err,
-};
-
-static const match_table_t tokens = {
-	{Opt_logbufs,	"logbufs=%u"},	/* number of XFS log buffers */
-	{Opt_logbsize,	"logbsize=%s"},	/* size of XFS log buffers */
-	{Opt_logdev,	"logdev=%s"},	/* log device */
-	{Opt_rtdev,	"rtdev=%s"},	/* realtime I/O device */
-	{Opt_wsync,	"wsync"},	/* safe-mode nfs compatible mount */
-	{Opt_noalign,	"noalign"},	/* turn off stripe alignment */
-	{Opt_swalloc,	"swalloc"},	/* turn on stripe width allocation */
-	{Opt_sunit,	"sunit=%u"},	/* data volume stripe unit */
-	{Opt_swidth,	"swidth=%u"},	/* data volume stripe width */
-	{Opt_nouuid,	"nouuid"},	/* ignore filesystem UUID */
-	{Opt_grpid,	"grpid"},	/* group-ID from parent directory */
-	{Opt_nogrpid,	"nogrpid"},	/* group-ID from current process */
-	{Opt_bsdgroups,	"bsdgroups"},	/* group-ID from parent directory */
-	{Opt_sysvgroups,"sysvgroups"},	/* group-ID from current process */
-	{Opt_allocsize,	"allocsize=%s"},/* preferred allocation size */
-	{Opt_norecovery,"norecovery"},	/* don't run XFS recovery */
-	{Opt_inode64,	"inode64"},	/* inodes can be allocated anywhere */
-	{Opt_inode32,   "inode32"},	/* inode allocation limited to
-					 * XFS_MAXINUMBER_32 */
-	{Opt_ikeep,	"ikeep"},	/* do not free empty inode clusters */
-	{Opt_noikeep,	"noikeep"},	/* free empty inode clusters */
-	{Opt_largeio,	"largeio"},	/* report large I/O sizes in stat() */
-	{Opt_nolargeio,	"nolargeio"},	/* do not report large I/O sizes
-					 * in stat(). */
-	{Opt_attr2,	"attr2"},	/* do use attr2 attribute format */
-	{Opt_noattr2,	"noattr2"},	/* do not use attr2 attribute format */
-	{Opt_filestreams,"filestreams"},/* use filestreams allocator */
-	{Opt_quota,	"quota"},	/* disk quotas (user) */
-	{Opt_noquota,	"noquota"},	/* no quotas */
-	{Opt_usrquota,	"usrquota"},	/* user quota enabled */
-	{Opt_grpquota,	"grpquota"},	/* group quota enabled */
-	{Opt_prjquota,	"prjquota"},	/* project quota enabled */
-	{Opt_uquota,	"uquota"},	/* user quota (IRIX variant) */
-	{Opt_gquota,	"gquota"},	/* group quota (IRIX variant) */
-	{Opt_pquota,	"pquota"},	/* project quota (IRIX variant) */
-	{Opt_uqnoenforce,"uqnoenforce"},/* user quota limit enforcement */
-	{Opt_gqnoenforce,"gqnoenforce"},/* group quota limit enforcement */
-	{Opt_pqnoenforce,"pqnoenforce"},/* project quota limit enforcement */
-	{Opt_qnoenforce, "qnoenforce"},	/* same as uqnoenforce */
-	{Opt_discard,	"discard"},	/* Discard unused blocks */
-	{Opt_nodiscard,	"nodiscard"},	/* Do not discard unused blocks */
-	{Opt_dax,	"dax"},		/* Enable direct access to bdev pages */
-	{Opt_err,	NULL},
+	Opt_discard, Opt_nodiscard, Opt_dax,
 };
 
 static const struct fs_parameter_spec xfs_param_specs[] = {

Re: [PATCH v5 17/17] xfs: mount-api - remove remaining legacy mount code

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 07:31:40PM +0800, Ian Kent wrote:
> Now that the new mount api is being used the remaining old mount
> code can be removed.

Needs to be folded into the previous patch instead of leaving dead code
around there.

Re: [PATCH v5 17/17] xfs: mount-api - remove remaining legacy mount code

[Ian Kent]

On Wed, 2019-10-09 at 08:10 -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 07:31:40PM +0800, Ian Kent wrote:
> > Now that the new mount api is being used the remaining old mount
> > code can be removed.
> 
> Needs to be folded into the previous patch instead of leaving dead
> code
> around there.

Right, I was tempted to do that after making some changes that
Brian suggested.

I'll do that too.

Ian

Re: [PATCH v5 00/17] xfs: mount API patch series

[Christoph Hellwig]

On Wed, Oct 09, 2019 at 07:30:10PM +0800, Ian Kent wrote:
>  fs/super.c                 |   97 +++++
>  fs/xfs/xfs_super.c         |  926 +++++++++++++++++++++++---------------------
>  include/linux/fs_context.h |    5 
>  3 files changed, 587 insertions(+), 441 deletions(-)

I am a little worried about the diffstat.  A few more lines of code
more for a more abstract API seems fine, but +150 lines for no new
functionality is worrisome.

Re: [PATCH v5 00/17] xfs: mount API patch series

[Ian Kent]

On Wed, 2019-10-09 at 07:52 -0700, Christoph Hellwig wrote:
> On Wed, Oct 09, 2019 at 07:30:10PM +0800, Ian Kent wrote:
> >  fs/super.c                 |   97 +++++
> >  fs/xfs/xfs_super.c         |  926 +++++++++++++++++++++++---------
> > ------------
> >  include/linux/fs_context.h |    5 
> >  3 files changed, 587 insertions(+), 441 deletions(-)
> 
> I am a little worried about the diffstat.  A few more lines of code
> more for a more abstract API seems fine, but +150 lines for no new
> functionality is worrisome.
> 

Right, that's an obvious and sensible sanity check.

But don't forget the first two patches are there for people
to use so they can test the series since they were not in
the xfs-linux tree at the time.

The first patch, to create the get_tree_bdev() function, has
been dropped because it's now been merged and the xfs-linux
tree has been updated.

There's also the bug fix to that patch which Al has now
pushed to Linus but is not yet in xfs-linux, so it's still
present in the series.

Without that first patch the diffstat is a bit better.

 fs/super.c         |    5 
 fs/xfs/xfs_super.c |  926 +++++++++++++++++++++++++++-------------------------
 2 files changed, 489 insertions(+), 442 deletions(-)

at 47 lines and once the bug fix patch makes its way to
xfs-linux this will be under 45 which might be ok since
overall I think there's an additional function.

Ian