From 4480c27ca3eaaaae134633a594fba5601da13b4a Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Wed, 8 Jun 2022 16:22:55 +0200 Subject: gfs2: Add glockfd debugfs file When a process has a gfs2 file open, the file is keeping a reference on the underlying gfs2 inode, and the inode is keeping the inode's iopen glock held in shared mode. In other words, the process depends on the iopen glock of each open gfs2 file. Expose those dependencies in a new "glockfd" debugfs file. The new debugfs file contains one line for each gfs2 file descriptor, specifying the tgid, file descriptor number, and glock name, e.g., 1601 6 5/816d This list is compiled by iterating all tasks on the system using find_ge_pid(), and all file descriptors of each task using task_lookup_next_fd_rcu(). To make that work from gfs2, export those two functions. Signed-off-by: Andreas Gruenbacher --- fs/gfs2/glock.c | 149 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 149 insertions(+) (limited to 'fs/gfs2') diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index c992d53013d3..85352126e662 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -33,6 +33,9 @@ #include #include #include +#include +#include +#include #include "gfs2.h" #include "incore.h" @@ -2745,6 +2748,149 @@ static const struct file_operations gfs2_glstats_fops = { .release = gfs2_glocks_release, }; +struct gfs2_glockfd_iter { + struct super_block *sb; + unsigned int tgid; + struct task_struct *task; + unsigned int fd; + struct file *file; +}; + +static struct task_struct *gfs2_glockfd_next_task(struct gfs2_glockfd_iter *i) +{ + struct pid_namespace *ns = task_active_pid_ns(current); + struct pid *pid; + + if (i->task) + put_task_struct(i->task); + + rcu_read_lock(); +retry: + i->task = NULL; + pid = find_ge_pid(i->tgid, ns); + if (pid) { + i->tgid = pid_nr_ns(pid, ns); + i->task = pid_task(pid, PIDTYPE_TGID); + if (!i->task) { + i->tgid++; + goto retry; + } + get_task_struct(i->task); + } + rcu_read_unlock(); + return i->task; +} + +static struct file *gfs2_glockfd_next_file(struct gfs2_glockfd_iter *i) +{ + if (i->file) { + fput(i->file); + i->file = NULL; + } + + rcu_read_lock(); + for(;; i->fd++) { + struct inode *inode; + + i->file = task_lookup_next_fd_rcu(i->task, &i->fd); + if (!i->file) { + i->fd = 0; + break; + } + inode = file_inode(i->file); + if (inode->i_sb != i->sb) + continue; + if (get_file_rcu(i->file)) + break; + } + rcu_read_unlock(); + return i->file; +} + +static void *gfs2_glockfd_seq_start(struct seq_file *seq, loff_t *pos) +{ + struct gfs2_glockfd_iter *i = seq->private; + + if (*pos) + return NULL; + while (gfs2_glockfd_next_task(i)) { + if (gfs2_glockfd_next_file(i)) + return i; + i->tgid++; + } + return NULL; +} + +static void *gfs2_glockfd_seq_next(struct seq_file *seq, void *iter_ptr, + loff_t *pos) +{ + struct gfs2_glockfd_iter *i = seq->private; + + (*pos)++; + i->fd++; + do { + if (gfs2_glockfd_next_file(i)) + return i; + i->tgid++; + } while (gfs2_glockfd_next_task(i)); + return NULL; +} + +static void gfs2_glockfd_seq_stop(struct seq_file *seq, void *iter_ptr) +{ + struct gfs2_glockfd_iter *i = seq->private; + + if (i->file) + fput(i->file); + if (i->task) + put_task_struct(i->task); +} + +static int gfs2_glockfd_seq_show(struct seq_file *seq, void *iter_ptr) +{ + struct gfs2_glockfd_iter *i = seq->private; + struct inode *inode = file_inode(i->file); + struct gfs2_glock *gl; + + inode_lock_shared(inode); + gl = GFS2_I(inode)->i_iopen_gh.gh_gl; + if (gl) { + seq_printf(seq, "%d %u %u/%llx\n", + i->tgid, i->fd, gl->gl_name.ln_type, + (unsigned long long)gl->gl_name.ln_number); + } + inode_unlock_shared(inode); + return 0; +} + +static const struct seq_operations gfs2_glockfd_seq_ops = { + .start = gfs2_glockfd_seq_start, + .next = gfs2_glockfd_seq_next, + .stop = gfs2_glockfd_seq_stop, + .show = gfs2_glockfd_seq_show, +}; + +static int gfs2_glockfd_open(struct inode *inode, struct file *file) +{ + struct gfs2_glockfd_iter *i; + struct gfs2_sbd *sdp = inode->i_private; + + i = __seq_open_private(file, &gfs2_glockfd_seq_ops, + sizeof(struct gfs2_glockfd_iter)); + if (!i) + return -ENOMEM; + i->sb = sdp->sd_vfs; + return 0; +} + +static const struct file_operations gfs2_glockfd_fops = { + .owner = THIS_MODULE, + .open = gfs2_glockfd_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_private, +}; + DEFINE_SEQ_ATTRIBUTE(gfs2_sbstats); void gfs2_create_debugfs_file(struct gfs2_sbd *sdp) @@ -2754,6 +2900,9 @@ void gfs2_create_debugfs_file(struct gfs2_sbd *sdp) debugfs_create_file("glocks", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp, &gfs2_glocks_fops); + debugfs_create_file("glockfd", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp, + &gfs2_glockfd_fops); + debugfs_create_file("glstats", S_IFREG | S_IRUGO, sdp->debugfs_dir, sdp, &gfs2_glstats_fops); -- cgit v1.2.3 From 56535dc695f8e215dffb9557d6bcbdf46ff785d2 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Thu, 23 Jun 2022 23:29:36 +0200 Subject: gfs2: Add flocks to glockfd debugfs file Include flock glocks in the "glockfd" debugfs file. Those are similar to the iopen glocks; while an open file is holding an flock, it is holding the file's flock glock. We cannot take f_fl_mutex in gfs2_glockfd_seq_show_flock() or else dumping the "glockfd" file would block on flock operations. Instead, use the file->f_lock spin lock to protect the f_fl_gh.gh_gl glock pointer. Signed-off-by: Andreas Gruenbacher --- fs/gfs2/file.c | 22 ++++++++++++++++++++-- fs/gfs2/glock.c | 23 +++++++++++++++++++++++ 2 files changed, 43 insertions(+), 2 deletions(-) (limited to 'fs/gfs2') diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index 2cceb193dcd8..25f4080bc973 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -1444,6 +1444,22 @@ static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl) return dlm_posix_lock(ls->ls_dlm, ip->i_no_addr, file, cmd, fl); } +static void __flock_holder_uninit(struct file *file, struct gfs2_holder *fl_gh) +{ + struct gfs2_glock *gl = fl_gh->gh_gl; + + /* + * Make sure gfs2_glock_put() won't sleep under the file->f_lock + * spinlock. + */ + + gfs2_glock_hold(gl); + spin_lock(&file->f_lock); + gfs2_holder_uninit(fl_gh); + spin_unlock(&file->f_lock); + gfs2_glock_put(gl); +} + static int do_flock(struct file *file, int cmd, struct file_lock *fl) { struct gfs2_file *fp = file->private_data; @@ -1475,7 +1491,9 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl) &gfs2_flock_glops, CREATE, &gl); if (error) goto out; + spin_lock(&file->f_lock); gfs2_holder_init(gl, state, flags, fl_gh); + spin_unlock(&file->f_lock); gfs2_glock_put(gl); } for (sleeptime = 1; sleeptime <= 4; sleeptime <<= 1) { @@ -1486,7 +1504,7 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl) msleep(sleeptime); } if (error) { - gfs2_holder_uninit(fl_gh); + __flock_holder_uninit(file, fl_gh); if (error == GLR_TRYFAILED) error = -EAGAIN; } else { @@ -1508,7 +1526,7 @@ static void do_unflock(struct file *file, struct file_lock *fl) locks_lock_file_wait(file, fl); if (gfs2_holder_initialized(fl_gh)) { gfs2_glock_dq(fl_gh); - gfs2_holder_uninit(fl_gh); + __flock_holder_uninit(file, fl_gh); } mutex_unlock(&fp->f_fl_mutex); } diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 85352126e662..533ec772166d 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -2846,6 +2846,28 @@ static void gfs2_glockfd_seq_stop(struct seq_file *seq, void *iter_ptr) put_task_struct(i->task); } +static void gfs2_glockfd_seq_show_flock(struct seq_file *seq, + struct gfs2_glockfd_iter *i) +{ + struct gfs2_file *fp = i->file->private_data; + struct gfs2_holder *fl_gh = &fp->f_fl_gh; + struct lm_lockname gl_name = { .ln_type = LM_TYPE_RESERVED }; + + if (!READ_ONCE(fl_gh->gh_gl)) + return; + + spin_lock(&i->file->f_lock); + if (gfs2_holder_initialized(fl_gh)) + gl_name = fl_gh->gh_gl->gl_name; + spin_unlock(&i->file->f_lock); + + if (gl_name.ln_type != LM_TYPE_RESERVED) { + seq_printf(seq, "%d %u %u/%llx\n", + i->tgid, i->fd, gl_name.ln_type, + (unsigned long long)gl_name.ln_number); + } +} + static int gfs2_glockfd_seq_show(struct seq_file *seq, void *iter_ptr) { struct gfs2_glockfd_iter *i = seq->private; @@ -2859,6 +2881,7 @@ static int gfs2_glockfd_seq_show(struct seq_file *seq, void *iter_ptr) i->tgid, i->fd, gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number); } + gfs2_glockfd_seq_show_flock(seq, i); inode_unlock_shared(inode); return 0; } -- cgit v1.2.3 From cbe6d2576e2cf7571e781439728ad31bdfd9dfcb Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Tue, 5 Apr 2022 22:07:30 +0200 Subject: gfs2: Add GL_NOPID flag for process-independent glock holders Add a GL_NOPID flag to indicate that once a glock holder has been acquired, it won't be associated with the current process anymore. This is useful for iopen and flock glocks which are associated with open files, as well as journal glock holders and similar which are associated with the filesystem. Once GL_NOPID is used for all applicable glocks (see the next patches), processes will no longer be falsely reported as holding glocks which they are not actually holding in the glocks dump file. Unlike before, when a process is reported as having "(ended)", this will indicate an actual bug. Signed-off-by: Andreas Gruenbacher --- fs/gfs2/glock.c | 41 +++++++++++++++++++++++++++++++---------- fs/gfs2/glock.h | 1 + 2 files changed, 32 insertions(+), 10 deletions(-) (limited to 'fs/gfs2') diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 533ec772166d..f80fba5d1d4d 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1467,6 +1467,15 @@ void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...) va_end(args); } +static inline bool pid_is_meaningful(const struct gfs2_holder *gh) +{ + if (!(gh->gh_flags & GL_NOPID)) + return true; + if (gh->gh_state == LM_ST_UNLOCKED) + return true; + return false; +} + /** * add_to_queue - Add a holder to the wait queue (but look for recursion) * @gh: the holder structure to add @@ -1503,10 +1512,17 @@ __acquires(&gl->gl_lockref.lock) } list_for_each_entry(gh2, &gl->gl_holders, gh_list) { - if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid && - (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK) && - !test_bit(HIF_MAY_DEMOTE, &gh2->gh_iflags))) - goto trap_recursive; + if (likely(gh2->gh_owner_pid != gh->gh_owner_pid)) + continue; + if (gh->gh_gl->gl_ops->go_type == LM_TYPE_FLOCK) + continue; + if (test_bit(HIF_MAY_DEMOTE, &gh2->gh_iflags)) + continue; + if (!pid_is_meaningful(gh2)) + continue; + goto trap_recursive; + } + list_for_each_entry(gh2, &gl->gl_holders, gh_list) { if (try_futile && !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) { fail: @@ -2321,19 +2337,24 @@ static const char *hflags2str(char *buf, u16 flags, unsigned long iflags) static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh, const char *fs_id_buf) { - struct task_struct *gh_owner = NULL; + const char *comm = "(none)"; + pid_t owner_pid = 0; char flags_buf[32]; rcu_read_lock(); - if (gh->gh_owner_pid) + if (pid_is_meaningful(gh)) { + struct task_struct *gh_owner; + + comm = "(ended)"; + owner_pid = pid_nr(gh->gh_owner_pid); gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID); + if (gh_owner) + comm = gh_owner->comm; + } gfs2_print_dbg(seq, "%s H: s:%s f:%s e:%d p:%ld [%s] %pS\n", fs_id_buf, state2str(gh->gh_state), hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags), - gh->gh_error, - gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1, - gh_owner ? gh_owner->comm : "(ended)", - (void *)gh->gh_ip); + gh->gh_error, (long)owner_pid, comm, (void *)gh->gh_ip); rcu_read_unlock(); } diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h index c0ae9100a0bc..e764ebeba54c 100644 --- a/fs/gfs2/glock.h +++ b/fs/gfs2/glock.h @@ -91,6 +91,7 @@ enum { #define GL_ASYNC 0x0040 #define GL_EXACT 0x0080 #define GL_SKIP 0x0100 +#define GL_NOPID 0x0200 #define GL_NOCACHE 0x0400 /* -- cgit v1.2.3 From b582d5f05ddbd61bb72896b31ff83d7f0b0862f5 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Wed, 6 Apr 2022 12:51:27 +0200 Subject: gfs2: Mark flock glock holders as GL_NOPID Add the GL_NOPID flag for flock glock holders. Clean up the flag setting code in do_flock. Signed-off-by: Andreas Gruenbacher --- fs/gfs2/file.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'fs/gfs2') diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index 25f4080bc973..1383f9598011 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -1472,7 +1472,9 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl) int sleeptime; state = (fl->fl_type == F_WRLCK) ? LM_ST_EXCLUSIVE : LM_ST_SHARED; - flags = (IS_SETLKW(cmd) ? 0 : LM_FLAG_TRY_1CB) | GL_EXACT; + flags = GL_EXACT | GL_NOPID; + if (!IS_SETLKW(cmd)) + flags |= LM_FLAG_TRY_1CB; mutex_lock(&fp->f_fl_mutex); @@ -1500,7 +1502,8 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl) error = gfs2_glock_nq(fl_gh); if (error != GLR_TRYFAILED) break; - fl_gh->gh_flags = LM_FLAG_TRY | GL_EXACT; + fl_gh->gh_flags &= ~LM_FLAG_TRY_1CB; + fl_gh->gh_flags |= LM_FLAG_TRY; msleep(sleeptime); } if (error) { -- cgit v1.2.3 From ebdc416c9c0bed245d6cda92ae2a98483e513051 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Tue, 5 Apr 2022 22:39:16 +0200 Subject: gfs2: Mark the remaining process-independent glock holders as GL_NOPID Add the GL_NOPID flag for the remaining glock holders which are not associated with the current process. Signed-off-by: Andreas Gruenbacher --- fs/gfs2/inode.c | 6 ++++-- fs/gfs2/ops_fstype.c | 14 ++++++++------ fs/gfs2/super.c | 3 ++- fs/gfs2/util.c | 6 ++++-- 4 files changed, 18 insertions(+), 11 deletions(-) (limited to 'fs/gfs2') diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c index c8ec876f33ea..e211ed8636b5 100644 --- a/fs/gfs2/inode.c +++ b/fs/gfs2/inode.c @@ -143,7 +143,8 @@ struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type, if (blktype != GFS2_BLKST_UNLINKED) gfs2_cancel_delete_work(io_gl); - error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, GL_EXACT, + error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, + GL_EXACT | GL_NOPID, &ip->i_iopen_gh); gfs2_glock_put(io_gl); if (unlikely(error)) @@ -720,7 +721,8 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, error = insert_inode_locked4(inode, ip->i_no_addr, iget_test, &ip->i_no_addr); BUG_ON(error); - error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, GL_EXACT, &ip->i_iopen_gh); + error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, GL_EXACT | GL_NOPID, + &ip->i_iopen_gh); if (error) goto fail_gunlock2; diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index c9b423c874a3..904a2d47c4b3 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -403,7 +403,8 @@ static int init_locking(struct gfs2_sbd *sdp, struct gfs2_holder *mount_gh, error = gfs2_glock_nq_num(sdp, GFS2_MOUNT_LOCK, &gfs2_nondisk_glops, - LM_ST_EXCLUSIVE, LM_FLAG_NOEXP | GL_NOCACHE, + LM_ST_EXCLUSIVE, + LM_FLAG_NOEXP | GL_NOCACHE | GL_NOPID, mount_gh); if (error) { fs_err(sdp, "can't acquire mount glock: %d\n", error); @@ -413,7 +414,7 @@ static int init_locking(struct gfs2_sbd *sdp, struct gfs2_holder *mount_gh, error = gfs2_glock_nq_num(sdp, GFS2_LIVE_LOCK, &gfs2_nondisk_glops, LM_ST_SHARED, - LM_FLAG_NOEXP | GL_EXACT, + LM_FLAG_NOEXP | GL_EXACT | GL_NOPID, &sdp->sd_live_gh); if (error) { fs_err(sdp, "can't acquire live glock: %d\n", error); @@ -689,7 +690,7 @@ static int init_statfs(struct gfs2_sbd *sdp) iput(pn); pn = NULL; ip = GFS2_I(sdp->sd_sc_inode); - error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, + error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_NOPID, &sdp->sd_sc_gh); if (error) { fs_err(sdp, "can't lock local \"sc\" file: %d\n", error); @@ -778,7 +779,7 @@ static int init_journal(struct gfs2_sbd *sdp, int undo) error = gfs2_glock_nq_num(sdp, sdp->sd_lockstruct.ls_jid, &gfs2_journal_glops, LM_ST_EXCLUSIVE, - LM_FLAG_NOEXP | GL_NOCACHE, + LM_FLAG_NOEXP | GL_NOCACHE | GL_NOPID, &sdp->sd_journal_gh); if (error) { fs_err(sdp, "can't acquire journal glock: %d\n", error); @@ -788,7 +789,8 @@ static int init_journal(struct gfs2_sbd *sdp, int undo) ip = GFS2_I(sdp->sd_jdesc->jd_inode); sdp->sd_jinode_gl = ip->i_gl; error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, - LM_FLAG_NOEXP | GL_EXACT | GL_NOCACHE, + LM_FLAG_NOEXP | GL_EXACT | + GL_NOCACHE | GL_NOPID, &sdp->sd_jinode_gh); if (error) { fs_err(sdp, "can't acquire journal inode glock: %d\n", @@ -959,7 +961,7 @@ static int init_per_node(struct gfs2_sbd *sdp, int undo) pn = NULL; ip = GFS2_I(sdp->sd_qc_inode); - error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, + error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_NOPID, &sdp->sd_qc_gh); if (error) { fs_err(sdp, "can't lock local \"qc\" file: %d\n", error); diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index bdb773e5c88f..90db4a289269 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -346,7 +346,8 @@ static int gfs2_lock_fs_check_clean(struct gfs2_sbd *sdp) } error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_EXCLUSIVE, - LM_FLAG_NOEXP, &sdp->sd_freeze_gh); + LM_FLAG_NOEXP | GL_NOPID, + &sdp->sd_freeze_gh); if (error) goto out; diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c index 8241029a2a5d..95d733dd3c25 100644 --- a/fs/gfs2/util.c +++ b/fs/gfs2/util.c @@ -226,7 +226,8 @@ static void signal_our_withdraw(struct gfs2_sbd *sdp) */ fs_warn(sdp, "Requesting recovery of jid %d.\n", sdp->sd_lockstruct.ls_jid); - gfs2_holder_reinit(LM_ST_EXCLUSIVE, LM_FLAG_TRY_1CB | LM_FLAG_NOEXP, + gfs2_holder_reinit(LM_ST_EXCLUSIVE, + LM_FLAG_TRY_1CB | LM_FLAG_NOEXP | GL_NOPID, &sdp->sd_live_gh); msleep(GL_GLOCK_MAX_HOLD); /* @@ -251,7 +252,8 @@ static void signal_our_withdraw(struct gfs2_sbd *sdp) fs_warn(sdp, "Unable to recover our journal jid %d.\n", sdp->sd_lockstruct.ls_jid); gfs2_glock_dq_wait(&sdp->sd_live_gh); - gfs2_holder_reinit(LM_ST_SHARED, LM_FLAG_NOEXP | GL_EXACT, + gfs2_holder_reinit(LM_ST_SHARED, + LM_FLAG_NOEXP | GL_EXACT | GL_NOPID, &sdp->sd_live_gh); gfs2_glock_nq(&sdp->sd_live_gh); } -- cgit v1.2.3