Re: [PATCH v3 18/33] hpfs: don't set SB_RDONLY after filesystem errors

[sashiko-bot@kernel.org]

> With errors=remount-ro, the hpfs default, hpfs_error() sets SB_RDONLY on
> the first error without holding s_umount. If that happens while the
> filesystem is frozen through bdev_freeze() thaw_super() sees a read-only
> superblock and leaves the s_writers rwsems locked so every writer hangs.
> 
> hpfs_error() is also called from hpfs_fill_super() where nothing can
> freeze the superblock yet, so keep setting SB_RDONLY there. After that
> call sb_set_emergency_ro() instead and let the VFS refuse modifications.
> FITRIM is refused and unmark_dirty() does nothing in that state so the
> next mount reports the volume as improperly stopped. hpfs_map_dnode()
> and hpfs_lookup() treat the state like read-only so lookups behave as
> before.
> 
> 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 doesn't write the
> spare block. 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=18