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-rw-r--r--Documentation/filesystems/Locking21
1 files changed, 14 insertions, 7 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index f94a362f408e..c2963a74fbc3 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -342,7 +342,7 @@ prototypes:
locking rules:
- file_lock_lock may block
+ inode->i_lock may block
fl_copy_lock: yes no
fl_release_private: maybe no
@@ -355,12 +355,19 @@ prototypes:
int (*lm_change)(struct file_lock **, int);
locking rules:
- file_lock_lock may block
-lm_compare_owner: yes no
-lm_notify: yes no
-lm_grant: no no
-lm_break: yes no
-lm_change yes no
+
+ inode->i_lock file_lock_lock may block
+lm_compare_owner: yes[1] maybe no
+lm_notify: yes yes no
+lm_grant: no no no
+lm_break: yes no no
+lm_change yes no no
+
+[1]: ->lm_compare_owner is generally called with *an* inode->i_lock held. It
+may not be the i_lock of the inode for either file_lock being compared! This is
+the case with deadlock detection, since the code has to chase down the owners
+of locks that may be entirely unrelated to the one on which the lock is being
+acquired. When doing a search for deadlocks, the file_lock_lock is also held.
--------------------------- buffer_head -----------------------------------
prototypes:
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