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locks: convert posix locks to file_lock_context

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Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Jeff Layton
2015-01-16 15:05:55 -05:00
committed by Jeff Layton
parent 5263e31e45
commit bd61e0a9c8
11 changed files with 158 additions and 201 deletions
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110
fs/locks.c
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@@ -157,9 +157,6 @@ static int target_leasetype(struct file_lock *fl)
int leases_enable = 1;
int lease_break_time = 45;
#define for_each_lock(inode, lockp) \
for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)
/*
* The global file_lock_list is only used for displaying /proc/locks, so we
* keep a list on each CPU, with each list protected by its own spinlock via
@@ -218,6 +215,7 @@ locks_get_lock_context(struct inode *inode)
goto out;
INIT_LIST_HEAD(&new->flc_flock);
INIT_LIST_HEAD(&new->flc_posix);
/*
* Assign the pointer if it's not already assigned. If it is, then
@@ -241,6 +239,7 @@ locks_free_lock_context(struct file_lock_context *ctx)
{
if (ctx) {
WARN_ON_ONCE(!list_empty(&ctx->flc_flock));
WARN_ON_ONCE(!list_empty(&ctx->flc_posix));
kmem_cache_free(flctx_cache, ctx);
}
}
@@ -809,21 +808,26 @@ void
posix_test_lock(struct file *filp, struct file_lock *fl)
{
struct file_lock *cfl;
struct file_lock_context *ctx;
struct inode *inode = file_inode(filp);
spin_lock(&inode->i_lock);
for (cfl = file_inode(filp)->i_flock; cfl; cfl = cfl->fl_next) {
if (!IS_POSIX(cfl))
continue;
if (posix_locks_conflict(fl, cfl))
break;
}
if (cfl) {
locks_copy_conflock(fl, cfl);
if (cfl->fl_nspid)
fl->fl_pid = pid_vnr(cfl->fl_nspid);
} else
ctx = inode->i_flctx;
if (!ctx || list_empty_careful(&ctx->flc_posix)) {
fl->fl_type = F_UNLCK;
return;
}
spin_lock(&inode->i_lock);
list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
if (posix_locks_conflict(fl, cfl)) {
locks_copy_conflock(fl, cfl);
if (cfl->fl_nspid)
fl->fl_pid = pid_vnr(cfl->fl_nspid);
goto out;
}
}
fl->fl_type = F_UNLCK;
out:
spin_unlock(&inode->i_lock);
return;
}
@@ -983,16 +987,20 @@ out:
static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
{
struct file_lock *fl;
struct file_lock *fl, *tmp;
struct file_lock *new_fl = NULL;
struct file_lock *new_fl2 = NULL;
struct file_lock *left = NULL;
struct file_lock *right = NULL;
struct file_lock **before;
struct file_lock_context *ctx;
int error;
bool added = false;
LIST_HEAD(dispose);
ctx = locks_get_lock_context(inode);
if (!ctx)
return -ENOMEM;
/*
* We may need two file_lock structures for this operation,
* so we get them in advance to avoid races.
@@ -1013,8 +1021,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
* blocker's list of waiters and the global blocked_hash.
*/
if (request->fl_type != F_UNLCK) {
for_each_lock(inode, before) {
fl = *before;
list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
if (!IS_POSIX(fl))
continue;
if (!posix_locks_conflict(request, fl))
@@ -1044,29 +1051,25 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
if (request->fl_flags & FL_ACCESS)
goto out;
/*
* Find the first old lock with the same owner as the new lock.
*/
before = &inode->i_flock;
/* First skip locks owned by other processes. */
while ((fl = *before) && (!IS_POSIX(fl) ||
!posix_same_owner(request, fl))) {
before = &fl->fl_next;
/* Find the first old lock with the same owner as the new lock */
list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
if (posix_same_owner(request, fl))
break;
}
/* Process locks with this owner. */
while ((fl = *before) && posix_same_owner(request, fl)) {
/* Detect adjacent or overlapping regions (if same lock type)
*/
list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) {
if (!posix_same_owner(request, fl))
break;
/* Detect adjacent or overlapping regions (if same lock type) */
if (request->fl_type == fl->fl_type) {
/* In all comparisons of start vs end, use
* "start - 1" rather than "end + 1". If end
* is OFFSET_MAX, end + 1 will become negative.
*/
if (fl->fl_end < request->fl_start - 1)
goto next_lock;
continue;
/* If the next lock in the list has entirely bigger
* addresses than the new one, insert the lock here.
*/
@@ -1087,18 +1090,17 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
else
request->fl_end = fl->fl_end;
if (added) {
locks_delete_lock(before, &dispose);
locks_delete_lock_ctx(fl, &dispose);
continue;
}
request = fl;
added = true;
}
else {
} else {
/* Processing for different lock types is a bit
* more complex.
*/
if (fl->fl_end < request->fl_start)
goto next_lock;
continue;
if (fl->fl_start > request->fl_end)
break;
if (request->fl_type == F_UNLCK)
@@ -1117,7 +1119,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
* one (This may happen several times).
*/
if (added) {
locks_delete_lock(before, &dispose);
locks_delete_lock_ctx(fl, &dispose);
continue;
}
/*
@@ -1133,15 +1135,11 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
locks_copy_lock(new_fl, request);
request = new_fl;
new_fl = NULL;
locks_delete_lock(before, &dispose);
locks_insert_lock(before, request);
locks_insert_lock_ctx(request, &fl->fl_list);
locks_delete_lock_ctx(fl, &dispose);
added = true;
}
}
/* Go on to next lock.
*/
next_lock:
before = &fl->fl_next;
}
/*
@@ -1166,7 +1164,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
goto out;
}
locks_copy_lock(new_fl, request);
locks_insert_lock(before, new_fl);
locks_insert_lock_ctx(new_fl, &fl->fl_list);
new_fl = NULL;
}
if (right) {
@@ -1177,7 +1175,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
left = new_fl2;
new_fl2 = NULL;
locks_copy_lock(left, right);
locks_insert_lock(before, left);
locks_insert_lock_ctx(left, &fl->fl_list);
}
right->fl_start = request->fl_end + 1;
locks_wake_up_blocks(right);
@@ -1257,22 +1255,29 @@ EXPORT_SYMBOL(posix_lock_file_wait);
*/
int locks_mandatory_locked(struct file *file)
{
int ret;
struct inode *inode = file_inode(file);
struct file_lock_context *ctx;
struct file_lock *fl;
ctx = inode->i_flctx;
if (!ctx || list_empty_careful(&ctx->flc_posix))
return 0;
/*
* Search the lock list for this inode for any POSIX locks.
*/
spin_lock(&inode->i_lock);
for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
if (!IS_POSIX(fl))
continue;
ret = 0;
list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
if (fl->fl_owner != current->files &&
fl->fl_owner != file)
fl->fl_owner != file) {
ret = -EAGAIN;
break;
}
}
spin_unlock(&inode->i_lock);
return fl ? -EAGAIN : 0;
return ret;
}
/**
@@ -2389,13 +2394,14 @@ out:
void locks_remove_posix(struct file *filp, fl_owner_t owner)
{
struct file_lock lock;
struct file_lock_context *ctx = file_inode(filp)->i_flctx;
/*
* If there are no locks held on this file, we don't need to call
* posix_lock_file(). Another process could be setting a lock on this
* file at the same time, but we wouldn't remove that lock anyway.
*/
if (!file_inode(filp)->i_flock)
if (!ctx || list_empty(&ctx->flc_posix))
return;
lock.fl_type = F_UNLCK;