diff options
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/filesystems/Locking | 15 |
1 files changed, 4 insertions, 11 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 680fb566b928..8362860e21a7 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking | |||
@@ -144,8 +144,8 @@ prototypes: | |||
144 | void (*kill_sb) (struct super_block *); | 144 | void (*kill_sb) (struct super_block *); |
145 | locking rules: | 145 | locking rules: |
146 | may block BKL | 146 | may block BKL |
147 | get_sb yes yes | 147 | get_sb yes no |
148 | kill_sb yes yes | 148 | kill_sb yes no |
149 | 149 | ||
150 | ->get_sb() returns error or 0 with locked superblock attached to the vfsmount | 150 | ->get_sb() returns error or 0 with locked superblock attached to the vfsmount |
151 | (exclusive on ->s_umount). | 151 | (exclusive on ->s_umount). |
@@ -409,12 +409,12 @@ ioctl: yes (see below) | |||
409 | unlocked_ioctl: no (see below) | 409 | unlocked_ioctl: no (see below) |
410 | compat_ioctl: no | 410 | compat_ioctl: no |
411 | mmap: no | 411 | mmap: no |
412 | open: maybe (see below) | 412 | open: no |
413 | flush: no | 413 | flush: no |
414 | release: no | 414 | release: no |
415 | fsync: no (see below) | 415 | fsync: no (see below) |
416 | aio_fsync: no | 416 | aio_fsync: no |
417 | fasync: yes (see below) | 417 | fasync: no |
418 | lock: yes | 418 | lock: yes |
419 | readv: no | 419 | readv: no |
420 | writev: no | 420 | writev: no |
@@ -431,13 +431,6 @@ For many filesystems, it is probably safe to acquire the inode | |||
431 | semaphore. Note some filesystems (i.e. remote ones) provide no | 431 | semaphore. Note some filesystems (i.e. remote ones) provide no |
432 | protection for i_size so you will need to use the BKL. | 432 | protection for i_size so you will need to use the BKL. |
433 | 433 | ||
434 | ->open() locking is in-transit: big lock partially moved into the methods. | ||
435 | The only exception is ->open() in the instances of file_operations that never | ||
436 | end up in ->i_fop/->proc_fops, i.e. ones that belong to character devices | ||
437 | (chrdev_open() takes lock before replacing ->f_op and calling the secondary | ||
438 | method. As soon as we fix the handling of module reference counters all | ||
439 | instances of ->open() will be called without the BKL. | ||
440 | |||
441 | Note: ext2_release() was *the* source of contention on fs-intensive | 434 | Note: ext2_release() was *the* source of contention on fs-intensive |
442 | loads and dropping BKL on ->release() helps to get rid of that (we still | 435 | loads and dropping BKL on ->release() helps to get rid of that (we still |
443 | grab BKL for cases when we close a file that had been opened r/w, but that | 436 | grab BKL for cases when we close a file that had been opened r/w, but that |