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-rw-r--r--Documentation/filesystems/Locking43
1 files changed, 28 insertions, 15 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 0706d32a61e6..fe7afe225381 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -11,10 +11,8 @@ be able to use diff(1).
11prototypes: 11prototypes:
12 int (*d_revalidate)(struct dentry *, unsigned int); 12 int (*d_revalidate)(struct dentry *, unsigned int);
13 int (*d_weak_revalidate)(struct dentry *, unsigned int); 13 int (*d_weak_revalidate)(struct dentry *, unsigned int);
14 int (*d_hash)(const struct dentry *, const struct inode *, 14 int (*d_hash)(const struct dentry *, struct qstr *);
15 struct qstr *); 15 int (*d_compare)(const struct dentry *, const struct dentry *,
16 int (*d_compare)(const struct dentry *, const struct inode *,
17 const struct dentry *, const struct inode *,
18 unsigned int, const char *, const struct qstr *); 16 unsigned int, const char *, const struct qstr *);
19 int (*d_delete)(struct dentry *); 17 int (*d_delete)(struct dentry *);
20 void (*d_release)(struct dentry *); 18 void (*d_release)(struct dentry *);
@@ -66,6 +64,7 @@ prototypes:
66 int (*atomic_open)(struct inode *, struct dentry *, 64 int (*atomic_open)(struct inode *, struct dentry *,
67 struct file *, unsigned open_flag, 65 struct file *, unsigned open_flag,
68 umode_t create_mode, int *opened); 66 umode_t create_mode, int *opened);
67 int (*tmpfile) (struct inode *, struct dentry *, umode_t);
69 68
70locking rules: 69locking rules:
71 all may block 70 all may block
@@ -93,6 +92,7 @@ removexattr: yes
93fiemap: no 92fiemap: no
94update_time: no 93update_time: no
95atomic_open: yes 94atomic_open: yes
95tmpfile: no
96 96
97 Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on 97 Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
98victim. 98victim.
@@ -189,7 +189,7 @@ prototypes:
189 loff_t pos, unsigned len, unsigned copied, 189 loff_t pos, unsigned len, unsigned copied,
190 struct page *page, void *fsdata); 190 struct page *page, void *fsdata);
191 sector_t (*bmap)(struct address_space *, sector_t); 191 sector_t (*bmap)(struct address_space *, sector_t);
192 int (*invalidatepage) (struct page *, unsigned long); 192 void (*invalidatepage) (struct page *, unsigned int, unsigned int);
193 int (*releasepage) (struct page *, int); 193 int (*releasepage) (struct page *, int);
194 void (*freepage)(struct page *); 194 void (*freepage)(struct page *);
195 int (*direct_IO)(int, struct kiocb *, const struct iovec *iov, 195 int (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
@@ -310,8 +310,8 @@ filesystems and by the swapper. The latter will eventually go away. Please,
310keep it that way and don't breed new callers. 310keep it that way and don't breed new callers.
311 311
312 ->invalidatepage() is called when the filesystem must attempt to drop 312 ->invalidatepage() is called when the filesystem must attempt to drop
313some or all of the buffers from the page when it is being truncated. It 313some or all of the buffers from the page when it is being truncated. It
314returns zero on success. If ->invalidatepage is zero, the kernel uses 314returns zero on success. If ->invalidatepage is zero, the kernel uses
315block_invalidatepage() instead. 315block_invalidatepage() instead.
316 316
317 ->releasepage() is called when the kernel is about to try to drop the 317 ->releasepage() is called when the kernel is about to try to drop the
@@ -344,25 +344,38 @@ prototypes:
344 344
345 345
346locking rules: 346locking rules:
347 file_lock_lock may block 347 inode->i_lock may block
348fl_copy_lock: yes no 348fl_copy_lock: yes no
349fl_release_private: maybe no 349fl_release_private: maybe no
350 350
351----------------------- lock_manager_operations --------------------------- 351----------------------- lock_manager_operations ---------------------------
352prototypes: 352prototypes:
353 int (*lm_compare_owner)(struct file_lock *, struct file_lock *); 353 int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
354 unsigned long (*lm_owner_key)(struct file_lock *);
354 void (*lm_notify)(struct file_lock *); /* unblock callback */ 355 void (*lm_notify)(struct file_lock *); /* unblock callback */
355 int (*lm_grant)(struct file_lock *, struct file_lock *, int); 356 int (*lm_grant)(struct file_lock *, struct file_lock *, int);
356 void (*lm_break)(struct file_lock *); /* break_lease callback */ 357 void (*lm_break)(struct file_lock *); /* break_lease callback */
357 int (*lm_change)(struct file_lock **, int); 358 int (*lm_change)(struct file_lock **, int);
358 359
359locking rules: 360locking rules:
360 file_lock_lock may block 361
361lm_compare_owner: yes no 362 inode->i_lock blocked_lock_lock may block
362lm_notify: yes no 363lm_compare_owner: yes[1] maybe no
363lm_grant: no no 364lm_owner_key yes[1] yes no
364lm_break: yes no 365lm_notify: yes yes no
365lm_change yes no 366lm_grant: no no no
367lm_break: yes no no
368lm_change yes no no
369
370[1]: ->lm_compare_owner and ->lm_owner_key are generally called with
371*an* inode->i_lock held. It may not be the i_lock of the inode
372associated with either file_lock argument! This is the case with deadlock
373detection, since the code has to chase down the owners of locks that may
374be entirely unrelated to the one on which the lock is being acquired.
375For deadlock detection however, the blocked_lock_lock is also held. The
376fact that these locks are held ensures that the file_locks do not
377disappear out from under you while doing the comparison or generating an
378owner key.
366 379
367--------------------------- buffer_head ----------------------------------- 380--------------------------- buffer_head -----------------------------------
368prototypes: 381prototypes:
@@ -414,7 +427,7 @@ prototypes:
414 ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); 427 ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
415 ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t); 428 ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
416 ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t); 429 ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
417 int (*readdir) (struct file *, void *, filldir_t); 430 int (*iterate) (struct file *, struct dir_context *);
418 unsigned int (*poll) (struct file *, struct poll_table_struct *); 431 unsigned int (*poll) (struct file *, struct poll_table_struct *);
419 long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long); 432 long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
420 long (*compat_ioctl) (struct file *, unsigned int, unsigned long); 433 long (*compat_ioctl) (struct file *, unsigned int, unsigned long);