From: Dave Chinner dchinner@redhat.com
mainline inclusion from mainline-v5.14-rc4 commit e23b55d537c9be60ae918fa6c3be0d699986f346 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4KIAO CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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The attr2 feature is somewhat unique in that it has both a superblock feature bit to enable it and mount options to enable and disable it.
Back when it was first introduced in 2005, attr2 was disabled unless either the attr2 superblock feature bit was set, or the attr2 mount option was set. If the superblock feature bit was not set but the mount option was set, then when the first attr2 format inode fork was created, it would set the superblock feature bit. This is as it should be - the superblock feature bit indicated the presence of the attr2 on disk format.
The noattr2 mount option, however, did not affect the superblock feature bit. If noattr2 was specified, the on-disk superblock feature bit was ignored and the code always just created attr1 format inode forks. If neither of the attr2 or noattr2 mounts option were specified, then the behaviour was determined by the superblock feature bit.
This was all pretty sane.
Fast foward 3 years, and we are dealing with fallout from the botched sb_features2 addition and having to deal with feature mismatches between the sb_features2 and sb_bad_features2 fields. The attr2 feature bit was one of these flags. The reconciliation was done well after mount option parsing and, unfortunately, the feature reconciliation had a bug where it ignored the noattr2 mount option.
For reasons lost to the mists of time, it was decided that resolving this issue in commit 7c12f296500e ("[XFS] Fix up noattr2 so that it will properly update the versionnum and features2 fields.") required noattr2 to clear the superblock attr2 feature bit. This greatly complicated the attr2 behaviour and broke rules about feature bits needing to be set when those specific features are present in the filesystem.
By complicated, I mean that it introduced problems due to feature bit interactions with log recovery. All of the superblock feature bit checks are done prior to log recovery, but if we crash after removing a feature bit, then on the next mount we see the feature bit in the unrecovered superblock, only to have it go away after the log has been replayed. This means our mount time feature processing could be all wrong.
Hence you can mount with noattr2, crash shortly afterwards, and mount again without attr2 or noattr2 and still have attr2 enabled because the second mount sees attr2 still enabled in the superblock before recovery runs and removes the feature bit. It's just a mess.
Further, this is all legacy code as the v5 format requires attr2 to be enabled at all times and it cannot be disabled. i.e. the noattr2 mount option returns an error when used on v5 format filesystems.
To straighten this all out, this patch reverts the attr2/noattr2 mount option behaviour back to the original behaviour. There is no reason for disabling attr2 these days, so we will only do this when the noattr2 mount option is set. This will not remove the superblock feature bit. The superblock bit will provide the default behaviour and only track whether attr2 is present on disk or not. The attr2 mount option will enable the creation of attr2 format inode forks, and if the superblock feature bit is not set it will be added when the first attr2 inode fork is created.
Signed-off-by: Dave Chinner dchinner@redhat.com Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Long Li leo.lilong@huawei.com --- fs/xfs/libxfs/xfs_format.h | 7 ------- fs/xfs/xfs_mount.c | 27 ++++++++++----------------- fs/xfs/xfs_super.c | 16 +++++++--------- 3 files changed, 17 insertions(+), 33 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h index 8faa2a6069e6..3224d3514754 100644 --- a/fs/xfs/libxfs/xfs_format.h +++ b/fs/xfs/libxfs/xfs_format.h @@ -398,13 +398,6 @@ static inline void xfs_sb_version_addattr2(struct xfs_sb *sbp) sbp->sb_features2 |= XFS_SB_VERSION2_ATTR2BIT; }
-static inline void xfs_sb_version_removeattr2(struct xfs_sb *sbp) -{ - sbp->sb_features2 &= ~XFS_SB_VERSION2_ATTR2BIT; - if (!sbp->sb_features2) - sbp->sb_versionnum &= ~XFS_SB_VERSION_MOREBITSBIT; -} - static inline bool xfs_sb_version_hasprojid32bit(struct xfs_sb *sbp) { return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) || diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index 743c7ffdc316..142f88aa2c41 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -738,25 +738,8 @@ xfs_mountfs( xfs_warn(mp, "correcting sb_features alignment problem"); sbp->sb_features2 |= sbp->sb_bad_features2; mp->m_update_sb = true; - - /* - * Re-check for ATTR2 in case it was found in bad_features2 - * slot. - */ - if (xfs_sb_version_hasattr2(&mp->m_sb) && - !(mp->m_flags & XFS_MOUNT_NOATTR2)) - mp->m_flags |= XFS_MOUNT_ATTR2; }
- if (xfs_sb_version_hasattr2(&mp->m_sb) && - (mp->m_flags & XFS_MOUNT_NOATTR2)) { - xfs_sb_version_removeattr2(&mp->m_sb); - mp->m_update_sb = true; - - /* update sb_versionnum for the clearing of the morebits */ - if (!sbp->sb_features2) - mp->m_update_sb = true; - }
/* always use v2 inodes by default now */ if (!(mp->m_sb.sb_versionnum & XFS_SB_VERSION_NLINKBIT)) { @@ -921,6 +904,16 @@ xfs_mountfs( xfs_inodegc_start(mp); xfs_blockgc_start(mp);
+ /* + * Now that we've recovered any pending superblock feature bit + * additions, we can finish setting up the attr2 behaviour for the + * mount. If no attr2 mount options were specified, the we use the + * behaviour specified by the superblock feature bit. + */ + if (!(mp->m_flags & (XFS_MOUNT_ATTR2|XFS_MOUNT_NOATTR2)) && + xfs_sb_version_hasattr2(&mp->m_sb)) + mp->m_flags |= XFS_MOUNT_ATTR2; + /* * Get and sanity-check the root inode. * Save the pointer to it in the mount structure. diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index a79deea63a26..5f7478ddf2da 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -1007,14 +1007,6 @@ xfs_finish_flags( return -EINVAL; }
- /* - * mkfs'ed attr2 will turn on attr2 mount unless explicitly - * told by noattr2 to turn it off - */ - if (xfs_sb_version_hasattr2(&mp->m_sb) && - !(mp->m_flags & XFS_MOUNT_NOATTR2)) - mp->m_flags |= XFS_MOUNT_ATTR2; - /* * prohibit r/w mounts of read-only filesystems */ @@ -1377,7 +1369,6 @@ xfs_fc_parse_param( return 0; case Opt_noattr2: xfs_fs_warn_deprecated(fc, param, XFS_MOUNT_NOATTR2, true); - parsing_mp->m_flags &= ~XFS_MOUNT_ATTR2; parsing_mp->m_flags |= XFS_MOUNT_NOATTR2; return 0; default: @@ -1401,6 +1392,13 @@ xfs_fc_validate_params( return -EINVAL; }
+ if ((mp->m_flags & (XFS_MOUNT_ATTR2|XFS_MOUNT_NOATTR2)) == + (XFS_MOUNT_ATTR2|XFS_MOUNT_NOATTR2)) { + xfs_warn(mp, "attr2 and noattr2 cannot both be specified."); + return -EINVAL; + } + + if ((mp->m_flags & XFS_MOUNT_NOALIGN) && (mp->m_dalign || mp->m_swidth)) { xfs_warn(mp,