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| author | Darrick J. Wong <djwong@kernel.org> | 2023-07-17 19:00:09 +0300 |
|---|---|---|
| committer | Darrick J. Wong <djwong@kernel.org> | 2023-07-17 19:00:09 +0300 |
| commit | 880b9577855edddda1e732748e849c63199d489b (patch) | |
| tree | 8864baba5793708725a2c440be96c218846eeaef /fs/gfs2 | |
| parent | fdf0eaf11452d72945af31804e2a1048ee1b574c (diff) | |
| download | linux-880b9577855edddda1e732748e849c63199d489b.tar.xz | |
fs: distinguish between user initiated freeze and kernel initiated freeze
Userspace can freeze a filesystem using the FIFREEZE ioctl or by
suspending the block device; this state persists until userspace thaws
the filesystem with the FITHAW ioctl or resuming the block device.
Since commit 18e9e5104fcd ("Introduce freeze_super and thaw_super for
the fsfreeze ioctl") we only allow the first freeze command to succeed.
The kernel may decide that it is necessary to freeze a filesystem for
its own internal purposes, such as suspends in progress, filesystem fsck
activities, or quiescing a device prior to removal. Userspace thaw
commands must never break a kernel freeze, and kernel thaw commands
shouldn't undo userspace's freeze command.
Introduce a couple of freeze holder flags and wire it into the
sb_writers state. One kernel and one userspace freeze are allowed to
coexist at the same time; the filesystem will not thaw until both are
lifted.
I wonder if the f2fs/gfs2 code should be using a kernel freeze here, but
for now we'll use FREEZE_HOLDER_USERSPACE to preserve existing
behaviors.
Cc: mcgrof@kernel.org
Cc: jack@suse.cz
Cc: hch@infradead.org
Cc: ruansy.fnst@fujitsu.com
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/gfs2')
| -rw-r--r-- | fs/gfs2/super.c | 12 | ||||
| -rw-r--r-- | fs/gfs2/sys.c | 4 |
2 files changed, 9 insertions, 7 deletions
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index 9f4d5d6549ee..ae7fedc6ddcd 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -689,7 +689,7 @@ static int gfs2_freeze_locally(struct gfs2_sbd *sdp) struct super_block *sb = sdp->sd_vfs; int error; - error = freeze_super(sb); + error = freeze_super(sb, FREEZE_HOLDER_USERSPACE); if (error) return error; @@ -697,7 +697,9 @@ static int gfs2_freeze_locally(struct gfs2_sbd *sdp) gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_FREEZE | GFS2_LFC_FREEZE_GO_SYNC); if (gfs2_withdrawn(sdp)) { - thaw_super(sb); + error = thaw_super(sb, FREEZE_HOLDER_USERSPACE); + if (error) + return error; return -EIO; } } @@ -712,7 +714,7 @@ static int gfs2_do_thaw(struct gfs2_sbd *sdp) error = gfs2_freeze_lock_shared(sdp); if (error) goto fail; - error = thaw_super(sb); + error = thaw_super(sb, FREEZE_HOLDER_USERSPACE); if (!error) return 0; @@ -761,7 +763,7 @@ out: * */ -static int gfs2_freeze_super(struct super_block *sb) +static int gfs2_freeze_super(struct super_block *sb, enum freeze_holder who) { struct gfs2_sbd *sdp = sb->s_fs_info; int error; @@ -816,7 +818,7 @@ out: * */ -static int gfs2_thaw_super(struct super_block *sb) +static int gfs2_thaw_super(struct super_block *sb, enum freeze_holder who) { struct gfs2_sbd *sdp = sb->s_fs_info; int error; diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c index 2dfbe2f188dd..c60bc7f628e1 100644 --- a/fs/gfs2/sys.c +++ b/fs/gfs2/sys.c @@ -168,10 +168,10 @@ static ssize_t freeze_store(struct gfs2_sbd *sdp, const char *buf, size_t len) switch (n) { case 0: - error = thaw_super(sdp->sd_vfs); + error = thaw_super(sdp->sd_vfs, FREEZE_HOLDER_USERSPACE); break; case 1: - error = freeze_super(sdp->sd_vfs); + error = freeze_super(sdp->sd_vfs, FREEZE_HOLDER_USERSPACE); break; default: return -EINVAL; |