From: "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> To: qemu-devel@nongnu.org, stefanha@redhat.com, mreitz@redhat.com, misono.tomohiro@jp.fujitsu.com Cc: virtio-fs@redhat.com, vgoyal@Redhat.com Subject: [PULL 13/16] virtiofsd: Store every lo_inode's parent_dev Date: Mon, 26 Oct 2020 18:43:28 +0000 [thread overview] Message-ID: <20201026184331.272953-14-dgilbert@redhat.com> (raw) In-Reply-To: <20201026184331.272953-1-dgilbert@redhat.com> From: Max Reitz <mreitz@redhat.com> We want to detect mount points in the shared tree. We report them to the guest by setting the FUSE_ATTR_SUBMOUNT flag in fuse_attr.flags, but because the FUSE client will create a submount for every directory that has this flag set, we must do this only for the actual mount points. We can detect mount points by comparing a directory's st_dev with its parent's st_dev. To be able to do so, we need to store the parent's st_dev in the lo_inode object. Note that mount points need not necessarily be directories; a single file can be a mount point as well. However, for the sake of simplicity let us ignore any non-directory mount points for now. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200909184028.262297-6-mreitz@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> --- tools/virtiofsd/passthrough_ll.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index a0beb986f3..4188bf3ad2 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -125,6 +125,14 @@ struct lo_inode { GHashTable *posix_locks; /* protected by lo_inode->plock_mutex */ mode_t filetype; + + /* + * So we can detect crossmount roots + * (As such, this only needs to be valid for directories. Note + * that files can have multiple parents due to hard links, and so + * their parent_dev may fluctuate.) + */ + dev_t parent_dev; }; struct lo_cred { @@ -847,6 +855,7 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name, g_hash_table_insert(lo->inodes, &inode->key, inode); pthread_mutex_unlock(&lo->mutex); } + inode->parent_dev = dir->key.dev; e->ino = inode->fuse_ino; lo_inode_put(lo, &inode); lo_inode_put(lo, &dir); @@ -1073,6 +1082,14 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t parent, fuse_log(FUSE_LOG_DEBUG, " %lli/%s -> %lli\n", (unsigned long long)parent, name, (unsigned long long)e.ino); + /* + * No need to update inode->parent_dev, because + * (1) We cannot, the inode now has more than one parent, + * (2) Directories cannot have more than one parent, so link() + * does not work for them; but parent_dev only needs to be + * valid for directories. + */ + fuse_reply_entry(req, &e); lo_inode_put(lo, &parent_inode); lo_inode_put(lo, &inode); -- 2.28.0
WARNING: multiple messages have this Message-ID (diff)
From: "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> To: qemu-devel@nongnu.org, stefanha@redhat.com, mreitz@redhat.com, misono.tomohiro@jp.fujitsu.com Cc: virtio-fs@redhat.com, vgoyal@redhat.com Subject: [Virtio-fs] [PULL 13/16] virtiofsd: Store every lo_inode's parent_dev Date: Mon, 26 Oct 2020 18:43:28 +0000 [thread overview] Message-ID: <20201026184331.272953-14-dgilbert@redhat.com> (raw) In-Reply-To: <20201026184331.272953-1-dgilbert@redhat.com> From: Max Reitz <mreitz@redhat.com> We want to detect mount points in the shared tree. We report them to the guest by setting the FUSE_ATTR_SUBMOUNT flag in fuse_attr.flags, but because the FUSE client will create a submount for every directory that has this flag set, we must do this only for the actual mount points. We can detect mount points by comparing a directory's st_dev with its parent's st_dev. To be able to do so, we need to store the parent's st_dev in the lo_inode object. Note that mount points need not necessarily be directories; a single file can be a mount point as well. However, for the sake of simplicity let us ignore any non-directory mount points for now. Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20200909184028.262297-6-mreitz@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> --- tools/virtiofsd/passthrough_ll.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index a0beb986f3..4188bf3ad2 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -125,6 +125,14 @@ struct lo_inode { GHashTable *posix_locks; /* protected by lo_inode->plock_mutex */ mode_t filetype; + + /* + * So we can detect crossmount roots + * (As such, this only needs to be valid for directories. Note + * that files can have multiple parents due to hard links, and so + * their parent_dev may fluctuate.) + */ + dev_t parent_dev; }; struct lo_cred { @@ -847,6 +855,7 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name, g_hash_table_insert(lo->inodes, &inode->key, inode); pthread_mutex_unlock(&lo->mutex); } + inode->parent_dev = dir->key.dev; e->ino = inode->fuse_ino; lo_inode_put(lo, &inode); lo_inode_put(lo, &dir); @@ -1073,6 +1082,14 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t parent, fuse_log(FUSE_LOG_DEBUG, " %lli/%s -> %lli\n", (unsigned long long)parent, name, (unsigned long long)e.ino); + /* + * No need to update inode->parent_dev, because + * (1) We cannot, the inode now has more than one parent, + * (2) Directories cannot have more than one parent, so link() + * does not work for them; but parent_dev only needs to be + * valid for directories. + */ + fuse_reply_entry(req, &e); lo_inode_put(lo, &parent_inode); lo_inode_put(lo, &inode); -- 2.28.0
next prev parent reply other threads:[~2020-10-26 18:55 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-10-26 18:43 [PULL 00/16] virtiofs queue Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 01/16] configure: add option for virtiofsd Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 02/16] virtiofsd: passthrough_ll: set FUSE_LOG_INFO as default log_level Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 03/16] virtiofsd: add container-friendly -o sandbox=chroot option Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 04/16] tools/virtiofsd: xattr name mappings: Add option Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 05/16] tools/virtiofsd: xattr name mappings: Map client xattr names Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 06/16] tools/virtiofsd: xattr name mappings: Map server " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 07/16] tools/virtiofsd: xattr name mapping examples Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 08/16] tools/virtiofsd: xattr name mappings: Simple 'map' Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 09/16] linux/fuse.h: Pull in from Linux Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 10/16] virtiofsd: Announce FUSE_ATTR_FLAGS Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 11/16] virtiofsd: Add attr_flags to fuse_entry_param Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 12/16] virtiofsd: Add fuse_reply_attr_with_flags() Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` Dr. David Alan Gilbert (git) [this message] 2020-10-26 18:43 ` [Virtio-fs] [PULL 13/16] virtiofsd: Store every lo_inode's parent_dev Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 14/16] virtiofsd: Announce sub-mount points Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 15/16] tests/acceptance/boot_linux: Accept SSH pubkey Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [PULL 16/16] tests/acceptance: Add virtiofs_submounts.py Dr. David Alan Gilbert (git) 2020-10-26 18:43 ` [Virtio-fs] " Dr. David Alan Gilbert (git) 2020-10-27 16:58 ` [PULL 00/16] virtiofs queue Peter Maydell 2020-10-27 16:58 ` [Virtio-fs] " Peter Maydell
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