diff options
author | Jim Schutt <jaschut@sandia.gov> | 2013-05-15 13:03:35 -0500 |
---|---|---|
committer | Alex Elder <elder@inktank.com> | 2013-05-17 12:45:48 -0500 |
commit | 39be95e9c8c0b5668c9f8806ffe29bf9f4bc0f40 (patch) | |
tree | 580f3e90a2175e7c9173cce615696c9972df4982 /fs/ceph | |
parent | c420276a532a10ef59849adc2681f45306166b89 (diff) | |
download | linux-39be95e9c8c0b5668c9f8806ffe29bf9f4bc0f40.tar.gz linux-39be95e9c8c0b5668c9f8806ffe29bf9f4bc0f40.tar.bz2 linux-39be95e9c8c0b5668c9f8806ffe29bf9f4bc0f40.zip |
ceph: ceph_pagelist_append might sleep while atomic
Ceph's encode_caps_cb() worked hard to not call __page_cache_alloc()
while holding a lock, but it's spoiled because ceph_pagelist_addpage()
always calls kmap(), which might sleep. Here's the result:
[13439.295457] ceph: mds0 reconnect start
[13439.300572] BUG: sleeping function called from invalid context at include/linux/highmem.h:58
[13439.309243] in_atomic(): 1, irqs_disabled(): 0, pid: 12059, name: kworker/1:1
. . .
[13439.376225] Call Trace:
[13439.378757] [<ffffffff81076f4c>] __might_sleep+0xfc/0x110
[13439.384353] [<ffffffffa03f4ce0>] ceph_pagelist_append+0x120/0x1b0 [libceph]
[13439.391491] [<ffffffffa0448fe9>] ceph_encode_locks+0x89/0x190 [ceph]
[13439.398035] [<ffffffff814ee849>] ? _raw_spin_lock+0x49/0x50
[13439.403775] [<ffffffff811cadf5>] ? lock_flocks+0x15/0x20
[13439.409277] [<ffffffffa045e2af>] encode_caps_cb+0x41f/0x4a0 [ceph]
[13439.415622] [<ffffffff81196748>] ? igrab+0x28/0x70
[13439.420610] [<ffffffffa045e9f8>] ? iterate_session_caps+0xe8/0x250 [ceph]
[13439.427584] [<ffffffffa045ea25>] iterate_session_caps+0x115/0x250 [ceph]
[13439.434499] [<ffffffffa045de90>] ? set_request_path_attr+0x2d0/0x2d0 [ceph]
[13439.441646] [<ffffffffa0462888>] send_mds_reconnect+0x238/0x450 [ceph]
[13439.448363] [<ffffffffa0464542>] ? ceph_mdsmap_decode+0x5e2/0x770 [ceph]
[13439.455250] [<ffffffffa0462e42>] check_new_map+0x352/0x500 [ceph]
[13439.461534] [<ffffffffa04631ad>] ceph_mdsc_handle_map+0x1bd/0x260 [ceph]
[13439.468432] [<ffffffff814ebc7e>] ? mutex_unlock+0xe/0x10
[13439.473934] [<ffffffffa043c612>] extra_mon_dispatch+0x22/0x30 [ceph]
[13439.480464] [<ffffffffa03f6c2c>] dispatch+0xbc/0x110 [libceph]
[13439.486492] [<ffffffffa03eec3d>] process_message+0x1ad/0x1d0 [libceph]
[13439.493190] [<ffffffffa03f1498>] ? read_partial_message+0x3e8/0x520 [libceph]
. . .
[13439.587132] ceph: mds0 reconnect success
[13490.720032] ceph: mds0 caps stale
[13501.235257] ceph: mds0 recovery completed
[13501.300419] ceph: mds0 caps renewed
Fix it up by encoding locks into a buffer first, and when the number
of encoded locks is stable, copy that into a ceph_pagelist.
[elder@inktank.com: abbreviated the stack info a bit.]
Cc: stable@vger.kernel.org # 3.4+
Signed-off-by: Jim Schutt <jaschut@sandia.gov>
Reviewed-by: Alex Elder <elder@inktank.com>
Diffstat (limited to 'fs/ceph')
-rw-r--r-- | fs/ceph/locks.c | 76 | ||||
-rw-r--r-- | fs/ceph/mds_client.c | 65 | ||||
-rw-r--r-- | fs/ceph/super.h | 9 |
3 files changed, 89 insertions, 61 deletions
diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c index a80ed18d64ff..ebbf680378e2 100644 --- a/fs/ceph/locks.c +++ b/fs/ceph/locks.c @@ -191,29 +191,23 @@ void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count) } /** - * Encode the flock and fcntl locks for the given inode into the pagelist. - * Format is: #fcntl locks, sequential fcntl locks, #flock locks, - * sequential flock locks. - * Must be called with lock_flocks() already held. - * If we encounter more of a specific lock type than expected, - * we return the value 1. + * Encode the flock and fcntl locks for the given inode into the ceph_filelock + * array. Must be called with lock_flocks() already held. + * If we encounter more of a specific lock type than expected, return -ENOSPC. */ -int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist, - int num_fcntl_locks, int num_flock_locks) +int ceph_encode_locks_to_buffer(struct inode *inode, + struct ceph_filelock *flocks, + int num_fcntl_locks, int num_flock_locks) { struct file_lock *lock; - struct ceph_filelock cephlock; int err = 0; int seen_fcntl = 0; int seen_flock = 0; - __le32 nlocks; + int l = 0; dout("encoding %d flock and %d fcntl locks", num_flock_locks, num_fcntl_locks); - nlocks = cpu_to_le32(num_fcntl_locks); - err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks)); - if (err) - goto fail; + for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) { if (lock->fl_flags & FL_POSIX) { ++seen_fcntl; @@ -221,20 +215,12 @@ int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist, err = -ENOSPC; goto fail; } - err = lock_to_ceph_filelock(lock, &cephlock); + err = lock_to_ceph_filelock(lock, &flocks[l]); if (err) goto fail; - err = ceph_pagelist_append(pagelist, &cephlock, - sizeof(struct ceph_filelock)); + ++l; } - if (err) - goto fail; } - - nlocks = cpu_to_le32(num_flock_locks); - err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks)); - if (err) - goto fail; for (lock = inode->i_flock; lock != NULL; lock = lock->fl_next) { if (lock->fl_flags & FL_FLOCK) { ++seen_flock; @@ -242,19 +228,51 @@ int ceph_encode_locks(struct inode *inode, struct ceph_pagelist *pagelist, err = -ENOSPC; goto fail; } - err = lock_to_ceph_filelock(lock, &cephlock); + err = lock_to_ceph_filelock(lock, &flocks[l]); if (err) goto fail; - err = ceph_pagelist_append(pagelist, &cephlock, - sizeof(struct ceph_filelock)); + ++l; } - if (err) - goto fail; } fail: return err; } +/** + * Copy the encoded flock and fcntl locks into the pagelist. + * Format is: #fcntl locks, sequential fcntl locks, #flock locks, + * sequential flock locks. + * Returns zero on success. + */ +int ceph_locks_to_pagelist(struct ceph_filelock *flocks, + struct ceph_pagelist *pagelist, + int num_fcntl_locks, int num_flock_locks) +{ + int err = 0; + __le32 nlocks; + + nlocks = cpu_to_le32(num_fcntl_locks); + err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks)); + if (err) + goto out_fail; + + err = ceph_pagelist_append(pagelist, flocks, + num_fcntl_locks * sizeof(*flocks)); + if (err) + goto out_fail; + + nlocks = cpu_to_le32(num_flock_locks); + err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks)); + if (err) + goto out_fail; + + err = ceph_pagelist_append(pagelist, + &flocks[num_fcntl_locks], + num_flock_locks * sizeof(*flocks)); +out_fail: + return err; +} + /* * Given a pointer to a lock, convert it to a ceph filelock */ diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index d9ca15255477..4d2920304be8 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -2478,39 +2478,44 @@ static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap, if (recon_state->flock) { int num_fcntl_locks, num_flock_locks; - struct ceph_pagelist_cursor trunc_point; - - ceph_pagelist_set_cursor(pagelist, &trunc_point); - do { - lock_flocks(); - ceph_count_locks(inode, &num_fcntl_locks, - &num_flock_locks); - rec.v2.flock_len = cpu_to_le32(2*sizeof(u32) + - (num_fcntl_locks+num_flock_locks) * - sizeof(struct ceph_filelock)); - unlock_flocks(); - - /* pre-alloc pagelist */ - ceph_pagelist_truncate(pagelist, &trunc_point); - err = ceph_pagelist_append(pagelist, &rec, reclen); - if (!err) - err = ceph_pagelist_reserve(pagelist, - rec.v2.flock_len); - - /* encode locks */ - if (!err) { - lock_flocks(); - err = ceph_encode_locks(inode, - pagelist, - num_fcntl_locks, - num_flock_locks); - unlock_flocks(); - } - } while (err == -ENOSPC); + struct ceph_filelock *flocks; + +encode_again: + lock_flocks(); + ceph_count_locks(inode, &num_fcntl_locks, &num_flock_locks); + unlock_flocks(); + flocks = kmalloc((num_fcntl_locks+num_flock_locks) * + sizeof(struct ceph_filelock), GFP_NOFS); + if (!flocks) { + err = -ENOMEM; + goto out_free; + } + lock_flocks(); + err = ceph_encode_locks_to_buffer(inode, flocks, + num_fcntl_locks, + num_flock_locks); + unlock_flocks(); + if (err) { + kfree(flocks); + if (err == -ENOSPC) + goto encode_again; + goto out_free; + } + /* + * number of encoded locks is stable, so copy to pagelist + */ + rec.v2.flock_len = cpu_to_le32(2*sizeof(u32) + + (num_fcntl_locks+num_flock_locks) * + sizeof(struct ceph_filelock)); + err = ceph_pagelist_append(pagelist, &rec, reclen); + if (!err) + err = ceph_locks_to_pagelist(flocks, pagelist, + num_fcntl_locks, + num_flock_locks); + kfree(flocks); } else { err = ceph_pagelist_append(pagelist, &rec, reclen); } - out_free: kfree(path); out_dput: diff --git a/fs/ceph/super.h b/fs/ceph/super.h index 8696be2ff679..7ccfdb4aea2e 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -822,8 +822,13 @@ extern const struct export_operations ceph_export_ops; extern int ceph_lock(struct file *file, int cmd, struct file_lock *fl); extern int ceph_flock(struct file *file, int cmd, struct file_lock *fl); extern void ceph_count_locks(struct inode *inode, int *p_num, int *f_num); -extern int ceph_encode_locks(struct inode *i, struct ceph_pagelist *p, - int p_locks, int f_locks); +extern int ceph_encode_locks_to_buffer(struct inode *inode, + struct ceph_filelock *flocks, + int num_fcntl_locks, + int num_flock_locks); +extern int ceph_locks_to_pagelist(struct ceph_filelock *flocks, + struct ceph_pagelist *pagelist, + int num_fcntl_locks, int num_flock_locks); extern int lock_to_ceph_filelock(struct file_lock *fl, struct ceph_filelock *c); /* debugfs.c */ |