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locks: remove i_have_this_lease check from __break_lease 

I think that the intent of this code was to ensure that a process won't
deadlock if it has one fd open with a lease on it and then breaks that
lease by opening another fd. In that case it'll treat the __break_lease
call as if it were non-blocking.

This seems wrong -- the process could (for instance) be multithreaded
and managing different fds via different threads. I also don't see any
mention of this limitation in the (somewhat sketchy) documentation.

Remove the check and the non-blocking behavior when i_have_this_lease
is true.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
This commit is contained in:
Jeff Layton 2014-09-01 14:27:43 -04:00
parent c45198eda2
commit 843c6b2f4c
1 changed files with 2 additions and 4 deletions
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6
fs/locks.c
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@ -1370,7 +1370,6 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
struct file_lock *new_fl, *flock; struct file_lock *new_fl, *flock;
struct file_lock *fl; struct file_lock *fl;
unsigned long break_time; unsigned long break_time;
int i_have_this_lease = 0;
bool lease_conflict = false; bool lease_conflict = false;
int want_write = (mode & O_ACCMODE) != O_RDONLY; int want_write = (mode & O_ACCMODE) != O_RDONLY;
LIST_HEAD(dispose); LIST_HEAD(dispose);
@ -1391,8 +1390,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) { for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) {
if (leases_conflict(fl, new_fl)) { if (leases_conflict(fl, new_fl)) {
lease_conflict = true; lease_conflict = true;
if (fl->fl_owner == current->files) break;
i_have_this_lease = 1;
} }
} }
if (!lease_conflict) if (!lease_conflict)
@ -1422,7 +1420,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
fl->fl_lmops->lm_break(fl); fl->fl_lmops->lm_break(fl);
} }
if (i_have_this_lease || (mode & O_NONBLOCK)) { if (mode & O_NONBLOCK) {
trace_break_lease_noblock(inode, new_fl); trace_break_lease_noblock(inode, new_fl);
error = -EWOULDBLOCK; error = -EWOULDBLOCK;
goto out; goto out;