5.15-stable review patch. If anyone has any objections, please let me know.
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From: Dave Chinner dchinner@redhat.com
commit d8d222e09dab84a17bb65dda4b94d01c565f5327 upstream.
Recently xfs/513 started failing on my test machines testing "-o ro,norecovery" mount options. This was being emitted in dmesg:
[ 9906.932724] XFS (pmem0): no-recovery mounts must be read-only.
Turns out, readonly mounts with the fsopen()/fsconfig() mount API have been busted since day zero. It's only taken 5 years for debian unstable to start using this "new" mount API, and shortly after this I noticed xfs/513 had started to fail as per above.
The syscall trace is:
fsopen("xfs", FSOPEN_CLOEXEC) = 3 mount_setattr(-1, NULL, 0, NULL, 0) = -1 EINVAL (Invalid argument) ..... fsconfig(3, FSCONFIG_SET_STRING, "source", "/dev/pmem0", 0) = 0 fsconfig(3, FSCONFIG_SET_FLAG, "ro", NULL, 0) = 0 fsconfig(3, FSCONFIG_SET_FLAG, "norecovery", NULL, 0) = 0 fsconfig(3, FSCONFIG_CMD_CREATE, NULL, NULL, 0) = -1 EINVAL (Invalid argument) close(3) = 0
Showing that the actual mount instantiation (FSCONFIG_CMD_CREATE) is what threw out the error.
During mount instantiation, we call xfs_fs_validate_params() which does:
/* No recovery flag requires a read-only mount */ if (xfs_has_norecovery(mp) && !xfs_is_readonly(mp)) { xfs_warn(mp, "no-recovery mounts must be read-only."); return -EINVAL; }
and xfs_is_readonly() checks internal mount flags for read only state. This state is set in xfs_init_fs_context() from the context superblock flag state:
/* * Copy binary VFS mount flags we are interested in. */ if (fc->sb_flags & SB_RDONLY) set_bit(XFS_OPSTATE_READONLY, &mp->m_opstate);
With the old mount API, all of the VFS specific superblock flags had already been parsed and set before xfs_init_fs_context() is called, so this all works fine.
However, in the brave new fsopen/fsconfig world, xfs_init_fs_context() is called from fsopen() context, before any VFS superblock have been set or parsed. Hence if we use fsopen(), the internal XFS readonly state is *never set*. Hence anything that depends on xfs_is_readonly() actually returning true for read only mounts is broken if fsopen() has been used to mount the filesystem.
Fix this by moving this internal state initialisation to xfs_fs_fill_super() before we attempt to validate the parameters that have been set prior to the FSCONFIG_CMD_CREATE call being made.
Signed-off-by: Dave Chinner dchinner@redhat.com Fixes: 73e5fff98b64 ("xfs: switch to use the new mount-api") cc: stable@vger.kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Chandan Babu R chandanbabu@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/xfs/xfs_super.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-)
--- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -1436,6 +1436,18 @@ xfs_fs_fill_super(
mp->m_super = sb;
+ /* + * Copy VFS mount flags from the context now that all parameter parsing + * is guaranteed to have been completed by either the old mount API or + * the newer fsopen/fsconfig API. + */ + if (fc->sb_flags & SB_RDONLY) + set_bit(XFS_OPSTATE_READONLY, &mp->m_opstate); + if (fc->sb_flags & SB_DIRSYNC) + mp->m_features |= XFS_FEAT_DIRSYNC; + if (fc->sb_flags & SB_SYNCHRONOUS) + mp->m_features |= XFS_FEAT_WSYNC; + error = xfs_fs_validate_params(mp); if (error) goto out_free_names; @@ -1910,6 +1922,11 @@ static const struct fs_context_operation .free = xfs_fs_free, };
+/* + * WARNING: do not initialise any parameters in this function that depend on + * mount option parsing having already been performed as this can be called from + * fsopen() before any parameters have been set. + */ static int xfs_init_fs_context( struct fs_context *fc) { @@ -1942,16 +1959,6 @@ static int xfs_init_fs_context( mp->m_logbsize = -1; mp->m_allocsize_log = 16; /* 64k */
- /* - * Copy binary VFS mount flags we are interested in. - */ - if (fc->sb_flags & SB_RDONLY) - set_bit(XFS_OPSTATE_READONLY, &mp->m_opstate); - if (fc->sb_flags & SB_DIRSYNC) - mp->m_features |= XFS_FEAT_DIRSYNC; - if (fc->sb_flags & SB_SYNCHRONOUS) - mp->m_features |= XFS_FEAT_WSYNC; - fc->s_fs_info = mp; fc->ops = &xfs_context_ops;