| Message ID | 20210109075903.208222-5-ebiggers@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | lazytime fix and cleanups | expand |
On Fri, Jan 08, 2021 at 11:58:55PM -0800, Eric Biggers wrote: > + if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false)) > + dirty_flags |= I_DIRTY_SYNC; fat does not support i_version updates, so this bit can be skipped.
On Fri 08-01-21 23:58:55, Eric Biggers wrote: > From: Eric Biggers <ebiggers@google.com> > > As was done for generic_update_time(), only pass I_DIRTY_TIME to > __mark_inode_dirty() when the inode's timestamps were actually updated > and lazytime is enabled. This avoids a weird edge case where > I_DIRTY_TIME could be set in i_state when lazytime isn't enabled. > > Signed-off-by: Eric Biggers <ebiggers@google.com> Looks good to me. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/fat/misc.c | 23 ++++++++++++----------- > 1 file changed, 12 insertions(+), 11 deletions(-) > > diff --git a/fs/fat/misc.c b/fs/fat/misc.c > index f1b2a1fc2a6a4..18a50a46b57f8 100644 > --- a/fs/fat/misc.c > +++ b/fs/fat/misc.c > @@ -329,22 +329,23 @@ EXPORT_SYMBOL_GPL(fat_truncate_time); > > int fat_update_time(struct inode *inode, struct timespec64 *now, int flags) > { > - int iflags = I_DIRTY_TIME; > - bool dirty = false; > + int dirty_flags = 0; > > if (inode->i_ino == MSDOS_ROOT_INO) > return 0; > > - fat_truncate_time(inode, now, flags); > - if (flags & S_VERSION) > - dirty = inode_maybe_inc_iversion(inode, false); > - if ((flags & (S_ATIME | S_CTIME | S_MTIME)) && > - !(inode->i_sb->s_flags & SB_LAZYTIME)) > - dirty = true; > + if (flags & (S_ATIME | S_CTIME | S_MTIME)) { > + fat_truncate_time(inode, now, flags); > + if (inode->i_sb->s_flags & SB_LAZYTIME) > + dirty_flags |= I_DIRTY_TIME; > + else > + dirty_flags |= I_DIRTY_SYNC; > + } > + > + if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false)) > + dirty_flags |= I_DIRTY_SYNC; > > - if (dirty) > - iflags |= I_DIRTY_SYNC; > - __mark_inode_dirty(inode, iflags); > + __mark_inode_dirty(inode, dirty_flags); > return 0; > } > EXPORT_SYMBOL_GPL(fat_update_time); > -- > 2.30.0 >
On Mon, Jan 11, 2021 at 11:52:01AM +0100, Christoph Hellwig wrote: > On Fri, Jan 08, 2021 at 11:58:55PM -0800, Eric Biggers wrote: > > + if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false)) > > + dirty_flags |= I_DIRTY_SYNC; > > fat does not support i_version updates, so this bit can be skipped. Is that really the case? Any filesystem (including fat) can be mounted with "iversion", which causes SB_I_VERSION to be set. A lot of filesystems (including fat) don't store i_version to disk, but it looks like it will still get updated in-memory. Could anything be relying on that? - Eric
On Mon, Jan 11, 2021 at 11:50:27AM -0800, Eric Biggers wrote: > On Mon, Jan 11, 2021 at 11:52:01AM +0100, Christoph Hellwig wrote: > > On Fri, Jan 08, 2021 at 11:58:55PM -0800, Eric Biggers wrote: > > > + if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false)) > > > + dirty_flags |= I_DIRTY_SYNC; > > > > fat does not support i_version updates, so this bit can be skipped. > > Is that really the case? Any filesystem (including fat) can be mounted with > "iversion", which causes SB_I_VERSION to be set. That's a bug. Filesystems taht don't support persistent i_version on disk need to clear SB_I_VERSION in their mount and remount paths because the VFS iversion mount option was a complete screwup from the start. > A lot of filesystems (including fat) don't store i_version to disk, but it looks > like it will still get updated in-memory. Could anything be relying on that? If they do, then they are broken by definition. i_version as reported to observers is defined as monotonically increasing with every change to the inode. i.e. it never goes backwards. Which, of course, it will do if you crash or even just unmount/mount a filesystem that doesn't persist it. Cheers, Dave.
On Mon, Jan 11, 2021 at 11:50:27AM -0800, Eric Biggers wrote: > On Mon, Jan 11, 2021 at 11:52:01AM +0100, Christoph Hellwig wrote: > > On Fri, Jan 08, 2021 at 11:58:55PM -0800, Eric Biggers wrote: > > > + if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false)) > > > + dirty_flags |= I_DIRTY_SYNC; > > > > fat does not support i_version updates, so this bit can be skipped. > > Is that really the case? Any filesystem (including fat) can be mounted with > "iversion", which causes SB_I_VERSION to be set. > > A lot of filesystems (including fat) don't store i_version to disk, but it looks > like it will still get updated in-memory. Could anything be relying on that? As Dave pointed out i_version can't really work for fat. But I guess that is indeed out of scope for this series, so let's go ahead with this version for now: Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/fat/misc.c b/fs/fat/misc.c index f1b2a1fc2a6a4..18a50a46b57f8 100644 --- a/fs/fat/misc.c +++ b/fs/fat/misc.c @@ -329,22 +329,23 @@ EXPORT_SYMBOL_GPL(fat_truncate_time); int fat_update_time(struct inode *inode, struct timespec64 *now, int flags) { - int iflags = I_DIRTY_TIME; - bool dirty = false; + int dirty_flags = 0; if (inode->i_ino == MSDOS_ROOT_INO) return 0; - fat_truncate_time(inode, now, flags); - if (flags & S_VERSION) - dirty = inode_maybe_inc_iversion(inode, false); - if ((flags & (S_ATIME | S_CTIME | S_MTIME)) && - !(inode->i_sb->s_flags & SB_LAZYTIME)) - dirty = true; + if (flags & (S_ATIME | S_CTIME | S_MTIME)) { + fat_truncate_time(inode, now, flags); + if (inode->i_sb->s_flags & SB_LAZYTIME) + dirty_flags |= I_DIRTY_TIME; + else + dirty_flags |= I_DIRTY_SYNC; + } + + if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false)) + dirty_flags |= I_DIRTY_SYNC; - if (dirty) - iflags |= I_DIRTY_SYNC; - __mark_inode_dirty(inode, iflags); + __mark_inode_dirty(inode, dirty_flags); return 0; } EXPORT_SYMBOL_GPL(fat_update_time);