Re: [PATCH v3 16/33] affs: don't set SB_RDONLY after filesystem errors

[sashiko-bot@kernel.org]

> affs_error() sets SB_RDONLY from whatever context hit the error and
> without holding s_umount. If that happens while the filesystem is frozen
> through bdev_freeze(), e.g. by a device mapper suspend, thaw_super()
> sees a read-only superblock and leaves the s_writers rwsems locked so
> every writer hangs.
> 
> So call sb_set_emergency_ro() instead and let the VFS refuse
> modifications. affs_commit_super() leaves the root block alone in that
> state. affs_write_inode() keeps working because writeback still writes
> the data and the bitmap and extension blocks the inode points at.
> 
> After a remount to read-only a remount to read-write fails until umount.
> A plain remount to read-write right after the error succeeds but the
> filesystem stays read-only. A remount to read-only works and keeps the
> bitmap around because evict and the last close still free blocks,
> affs_kill_sb() frees it. Writes through file descriptors opened before
> the error fail with EROFS.
> 
> Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261113-work-fs-sb_rdonly-v3-0-0be92bb73709@kernel.org?part=16