From: Bob Peterson rpeterso@redhat.com
[ Upstream commit 96b1454f2e8ede4c619fde405a1bb4e9ba8d218e ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/gfs2/ops_fstype.c | 31 +++++++++++++++++-------------- fs/gfs2/super.c | 23 ----------------------- fs/gfs2/util.c | 18 ++++++++++++++++-- 3 files changed, 33 insertions(+), 39 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;
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index 6b0e8c0bb110..ddd40c96f7a2 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -165,7 +165,6 @@ int gfs2_make_fs_rw(struct gfs2_sbd *sdp) { struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode); struct gfs2_glock *j_gl = ip->i_gl; - struct gfs2_holder freeze_gh; struct gfs2_log_header_host head; int error;
@@ -173,10 +172,6 @@ int gfs2_make_fs_rw(struct gfs2_sbd *sdp) if (error) return error;
- error = gfs2_freeze_lock(sdp, &freeze_gh, 0); - if (error) - goto fail_threads; - j_gl->gl_ops->go_inval(j_gl, DIO_METADATA); if (gfs2_withdrawn(sdp)) { error = -EIO; @@ -203,13 +198,9 @@ int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
set_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
- gfs2_freeze_unlock(&freeze_gh); - return 0;
fail: - gfs2_freeze_unlock(&freeze_gh); -fail_threads: if (sdp->sd_quotad_process) kthread_stop(sdp->sd_quotad_process); sdp->sd_quotad_process = NULL; @@ -609,21 +600,9 @@ static void gfs2_dirty_inode(struct inode *inode, int flags)
int gfs2_make_fs_ro(struct gfs2_sbd *sdp) { - struct gfs2_holder freeze_gh; int error = 0; int log_write_allowed = test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
- gfs2_holder_mark_uninitialized(&freeze_gh); - if (sdp->sd_freeze_gl && - !gfs2_glock_is_locked_by_me(sdp->sd_freeze_gl)) { - error = gfs2_freeze_lock(sdp, &freeze_gh, - log_write_allowed ? 0 : LM_FLAG_TRY); - if (error == GLR_TRYFAILED) - error = 0; - if (error && !gfs2_withdrawn(sdp)) - return error; - } - gfs2_flush_delete_work(sdp); if (!log_write_allowed && current == sdp->sd_quotad_process) fs_warn(sdp, "The quotad daemon is withdrawing.\n"); @@ -652,8 +631,6 @@ int gfs2_make_fs_ro(struct gfs2_sbd *sdp) atomic_read(&sdp->sd_reserving_log) == 0, HZ * 5); } - gfs2_freeze_unlock(&freeze_gh); - gfs2_quota_cleanup(sdp);
if (!log_write_allowed) diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c index c8d55055e495..a1ecb2b48250 100644 --- a/fs/gfs2/util.c +++ b/fs/gfs2/util.c @@ -123,6 +123,7 @@ static void signal_our_withdraw(struct gfs2_sbd *sdp) struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_glock *i_gl = ip->i_gl; u64 no_formal_ino = ip->i_no_formal_ino; + int log_write_allowed = test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags); int ret = 0; int tries;
@@ -143,8 +144,21 @@ static void signal_our_withdraw(struct gfs2_sbd *sdp) * therefore we need to clear SDF_JOURNAL_LIVE manually. */ clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags); - if (!sb_rdonly(sdp->sd_vfs)) - ret = gfs2_make_fs_ro(sdp); + if (!sb_rdonly(sdp->sd_vfs)) { + struct gfs2_holder freeze_gh; + + gfs2_holder_mark_uninitialized(&freeze_gh); + if (sdp->sd_freeze_gl && + !gfs2_glock_is_locked_by_me(sdp->sd_freeze_gl)) { + ret = gfs2_freeze_lock(sdp, &freeze_gh, + log_write_allowed ? 0 : LM_FLAG_TRY); + if (ret == GLR_TRYFAILED) + ret = 0; + } + if (!ret) + ret = gfs2_make_fs_ro(sdp); + gfs2_freeze_unlock(&freeze_gh); + }
if (sdp->sd_lockstruct.ls_ops->lm_lock == NULL) { /* lock_nolock */ if (!ret)