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-rw-r--r--Documentation/filesystems/Locking35
1 files changed, 24 insertions, 11 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 9858f337529c..fe7afe225381 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -11,10 +11,8 @@ be able to use diff(1).
prototypes:
int (*d_revalidate)(struct dentry *, unsigned int);
int (*d_weak_revalidate)(struct dentry *, unsigned int);
- int (*d_hash)(const struct dentry *, const struct inode *,
- struct qstr *);
- int (*d_compare)(const struct dentry *, const struct inode *,
- const struct dentry *, const struct inode *,
+ int (*d_hash)(const struct dentry *, struct qstr *);
+ int (*d_compare)(const struct dentry *, const struct dentry *,
unsigned int, const char *, const struct qstr *);
int (*d_delete)(struct dentry *);
void (*d_release)(struct dentry *);
@@ -66,6 +64,7 @@ prototypes:
int (*atomic_open)(struct inode *, struct dentry *,
struct file *, unsigned open_flag,
umode_t create_mode, int *opened);
+ int (*tmpfile) (struct inode *, struct dentry *, umode_t);
locking rules:
all may block
@@ -93,6 +92,7 @@ removexattr: yes
fiemap: no
update_time: no
atomic_open: yes
+tmpfile: no
Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
victim.
@@ -344,25 +344,38 @@ prototypes:
locking rules:
- file_lock_lock may block
+ inode->i_lock may block
fl_copy_lock: yes no
fl_release_private: maybe no
----------------------- lock_manager_operations ---------------------------
prototypes:
int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
+ unsigned long (*lm_owner_key)(struct file_lock *);
void (*lm_notify)(struct file_lock *); /* unblock callback */
int (*lm_grant)(struct file_lock *, struct file_lock *, int);
void (*lm_break)(struct file_lock *); /* break_lease callback */
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 blocked_lock_lock may block
+lm_compare_owner: yes[1] maybe no
+lm_owner_key yes[1] yes 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 and ->lm_owner_key are generally called with
+*an* inode->i_lock held. It may not be the i_lock of the inode
+associated with either file_lock argument! 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.
+For deadlock detection however, the blocked_lock_lock is also held. The
+fact that these locks are held ensures that the file_locks do not
+disappear out from under you while doing the comparison or generating an
+owner key.
--------------------------- buffer_head -----------------------------------
prototypes: