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author | Bob Peterson <rpeterso@redhat.com> | 2020-12-22 14:43:28 -0600 |
---|---|---|
committer | Andreas Gruenbacher <agruenba@redhat.com> | 2020-12-23 00:54:21 +0100 |
commit | 96b1454f2e8ede4c619fde405a1bb4e9ba8d218e (patch) | |
tree | ec254d75a0d52a626cf0b2da1eb769d381566275 /fs/gfs2/ops_fstype.c | |
parent | c77b52c0a137994ad796f44544c802b0b766e496 (diff) | |
download | linux-96b1454f2e8ede4c619fde405a1bb4e9ba8d218e.tar.gz linux-96b1454f2e8ede4c619fde405a1bb4e9ba8d218e.tar.bz2 linux-96b1454f2e8ede4c619fde405a1bb4e9ba8d218e.zip |
gfs2: move freeze glock outside the make_fs_rw and _ro functions
Before this patch, sister functions gfs2_make_fs_rw and gfs2_make_fs_ro locked
(held) the freeze glock by calling gfs2_freeze_lock and gfs2_freeze_unlock.
The problem is, not all the callers of gfs2_make_fs_ro should be doing this.
The three callers of gfs2_make_fs_ro are: remount (gfs2_reconfigure),
signal_our_withdraw, and unmount (gfs2_put_super). But when unmounting the
file system we can get into the following circular lock dependency:
deactivate_super
down_write(&s->s_umount); <-------------------------------------- s_umount
deactivate_locked_super
gfs2_kill_sb
kill_block_super
generic_shutdown_super
gfs2_put_super
gfs2_make_fs_ro
gfs2_glock_nq_init sd_freeze_gl
freeze_go_sync
if (freeze glock in SH)
freeze_super (vfs)
down_write(&sb->s_umount); <------- s_umount
This patch moves the hold of the freeze glock outside the two sister rw/ro
functions to their callers, but it doesn't request the glock from
gfs2_put_super, thus eliminating the circular dependency.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Diffstat (limited to 'fs/gfs2/ops_fstype.c')
-rw-r--r-- | fs/gfs2/ops_fstype.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index 4ee56f5e93cb..f2c6bbe5cdb8 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -1084,6 +1084,7 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc) int silent = fc->sb_flags & SB_SILENT; struct gfs2_sbd *sdp; struct gfs2_holder mount_gh; + struct gfs2_holder freeze_gh; int error; sdp = init_sbd(sb); @@ -1195,23 +1196,18 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc) goto fail_per_node; } - if (sb_rdonly(sb)) { - struct gfs2_holder freeze_gh; + error = gfs2_freeze_lock(sdp, &freeze_gh, 0); + if (error) + goto fail_per_node; - error = gfs2_freeze_lock(sdp, &freeze_gh, 0); - if (error) { - fs_err(sdp, "can't make FS RO: %d\n", error); - goto fail_per_node; - } - gfs2_freeze_unlock(&freeze_gh); - } else { + if (!sb_rdonly(sb)) error = gfs2_make_fs_rw(sdp); - if (error) { - fs_err(sdp, "can't make FS RW: %d\n", error); - goto fail_per_node; - } - } + gfs2_freeze_unlock(&freeze_gh); + if (error) { + fs_err(sdp, "can't make FS RW: %d\n", error); + goto fail_per_node; + } gfs2_glock_dq_uninit(&mount_gh); gfs2_online_uevent(sdp); return 0; @@ -1512,6 +1508,12 @@ static int gfs2_reconfigure(struct fs_context *fc) fc->sb_flags |= SB_RDONLY; if ((sb->s_flags ^ fc->sb_flags) & SB_RDONLY) { + struct gfs2_holder freeze_gh; + + error = gfs2_freeze_lock(sdp, &freeze_gh, 0); + if (error) + return -EINVAL; + if (fc->sb_flags & SB_RDONLY) { error = gfs2_make_fs_ro(sdp); if (error) @@ -1521,6 +1523,7 @@ static int gfs2_reconfigure(struct fs_context *fc) if (error) errorfc(fc, "unable to remount read-write"); } + gfs2_freeze_unlock(&freeze_gh); } sdp->sd_args = *newargs; |