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| author | Andy Adamson <andros@citi.umich.edu> | 2006-03-26 01:37:26 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-26 08:56:56 -0800 |
| commit | 5842add2f3b519111b6401f3a35862bd00a3aa7e (patch) | |
| tree | 299e5653ec2b7dfc9fa565920d7320bbf1c9c07e /fs/locks.c | |
| parent | 6dc0fe8f8b40854982929e4f24d8c65115769b60 (diff) | |
| download | linux-3.10-5842add2f3b519111b6401f3a35862bd00a3aa7e.tar.gz linux-3.10-5842add2f3b519111b6401f3a35862bd00a3aa7e.tar.bz2 linux-3.10-5842add2f3b519111b6401f3a35862bd00a3aa7e.zip | |
[PATCH] VFS,fs/locks.c,NFSD4: add race_free posix_lock_file_conf() interface
Lockd and the NFSv4 server both exercise a race condition where
posix_test_lock() is called either before or after posix_lock_file() to
deal with a denied lock request due to a conflicting lock.
Remove the race condition for the NFSv4 server by adding a new conflicting
lock parameter to __posix_lock_file() , changing the name to
__posix_lock_file_conf().
Keep posix_lock_file() interface, add posix_lock_conf() interface, both
call __posix_lock_file_conf().
[akpm@osdl.org: Put the EXPORT_SYMBOL() where it belongs]
Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/locks.c')
| -rw-r--r-- | fs/locks.c | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/fs/locks.c b/fs/locks.c index 4badf6a0e7b..4d9e71d43e7 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -792,9 +792,7 @@ out: return error; } -EXPORT_SYMBOL(posix_lock_file); - -static int __posix_lock_file(struct inode *inode, struct file_lock *request) +static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request, struct file_lock *conflock) { struct file_lock *fl; struct file_lock *new_fl, *new_fl2; @@ -818,6 +816,8 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request) continue; if (!posix_locks_conflict(request, fl)) continue; + if (conflock) + locks_copy_lock(conflock, fl); error = -EAGAIN; if (!(request->fl_flags & FL_SLEEP)) goto out; @@ -987,8 +987,24 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request) */ int posix_lock_file(struct file *filp, struct file_lock *fl) { - return __posix_lock_file(filp->f_dentry->d_inode, fl); + return __posix_lock_file_conf(filp->f_dentry->d_inode, fl, NULL); +} +EXPORT_SYMBOL(posix_lock_file); + +/** + * posix_lock_file_conf - Apply a POSIX-style lock to a file + * @filp: The file to apply the lock to + * @fl: The lock to be applied + * @conflock: Place to return a copy of the conflicting lock, if found. + * + * Except for the conflock parameter, acts just like posix_lock_file. + */ +int posix_lock_file_conf(struct file *filp, struct file_lock *fl, + struct file_lock *conflock) +{ + return __posix_lock_file_conf(filp->f_dentry->d_inode, fl, conflock); } +EXPORT_SYMBOL(posix_lock_file_conf); /** * posix_lock_file_wait - Apply a POSIX-style lock to a file @@ -1004,7 +1020,7 @@ int posix_lock_file_wait(struct file *filp, struct file_lock *fl) int error; might_sleep (); for (;;) { - error = __posix_lock_file(filp->f_dentry->d_inode, fl); + error = posix_lock_file(filp, fl); if ((error != -EAGAIN) || !(fl->fl_flags & FL_SLEEP)) break; error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); @@ -1076,7 +1092,7 @@ int locks_mandatory_area(int read_write, struct inode *inode, fl.fl_end = offset + count - 1; for (;;) { - error = __posix_lock_file(inode, &fl); + error = __posix_lock_file_conf(inode, &fl, NULL); if (error != -EAGAIN) break; if (!(fl.fl_flags & FL_SLEEP)) @@ -1689,7 +1705,7 @@ again: error = filp->f_op->lock(filp, cmd, file_lock); else { for (;;) { - error = __posix_lock_file(inode, file_lock); + error = posix_lock_file(filp, file_lock); if ((error != -EAGAIN) || (cmd == F_SETLK)) break; error = wait_event_interruptible(file_lock->fl_wait, @@ -1832,7 +1848,7 @@ again: error = filp->f_op->lock(filp, cmd, file_lock); else { for (;;) { - error = __posix_lock_file(inode, file_lock); + error = posix_lock_file(filp, file_lock); if ((error != -EAGAIN) || (cmd == F_SETLK64)) break; error = wait_event_interruptible(file_lock->fl_wait, |