AcoSail/kernel_optimize_test
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forked from luck/tmp_suning_uos_patched
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configfs_detach_prep(): make sure that wait_mutex won't go away

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grab a reference to dentry we'd got the sucker from, and return
that dentry via *wait, rather than just returning the address of
->i_mutex.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-04-12 00:37:59 -04:00
parent 779b839133
commit 48f35b7b73
1 changed files with 9 additions and 8 deletions
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17
fs/configfs/dir.c
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@ -494,7 +494,7 @@ static struct dentry * configfs_lookup(struct inode *dir,
* If there is an error, the caller will reset the flags via * If there is an error, the caller will reset the flags via
* configfs_detach_rollback(). * configfs_detach_rollback().
*/ */
static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex) static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
{ {
struct configfs_dirent *parent_sd = dentry->d_fsdata; struct configfs_dirent *parent_sd = dentry->d_fsdata;
struct configfs_dirent *sd; struct configfs_dirent *sd;
@ -515,8 +515,8 @@ static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex
if (sd->s_type & CONFIGFS_USET_DEFAULT) { if (sd->s_type & CONFIGFS_USET_DEFAULT) {
/* Abort if racing with mkdir() */ /* Abort if racing with mkdir() */
if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { if (sd->s_type & CONFIGFS_USET_IN_MKDIR) {
if (wait_mutex) if (wait)
*wait_mutex = &d_inode(sd->s_dentry)->i_mutex; *wait= dget(sd->s_dentry);
return -EAGAIN; return -EAGAIN;
} }
@ -524,7 +524,7 @@ static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex
* Yup, recursive. If there's a problem, blame * Yup, recursive. If there's a problem, blame
* deep nesting of default_groups * deep nesting of default_groups
*/ */
ret = configfs_detach_prep(sd->s_dentry, wait_mutex); ret = configfs_detach_prep(sd->s_dentry, wait);
if (!ret) if (!ret)
continue; continue;
} else } else
@ -1458,7 +1458,7 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
* the new link is temporarily attached * the new link is temporarily attached
*/ */
do { do {
struct mutex *wait_mutex; struct dentry *wait;
mutex_lock(&configfs_symlink_mutex); mutex_lock(&configfs_symlink_mutex);
spin_lock(&configfs_dirent_lock); spin_lock(&configfs_dirent_lock);
@ -1469,7 +1469,7 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
*/ */
ret = sd->s_dependent_count ? -EBUSY : 0; ret = sd->s_dependent_count ? -EBUSY : 0;
if (!ret) { if (!ret) {
ret = configfs_detach_prep(dentry, &wait_mutex); ret = configfs_detach_prep(dentry, &wait);
if (ret) if (ret)
configfs_detach_rollback(dentry); configfs_detach_rollback(dentry);
} }
@ -1483,8 +1483,9 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
} }
/* Wait until the racing operation terminates */ /* Wait until the racing operation terminates */
mutex_lock(wait_mutex); inode_lock(d_inode(wait));
mutex_unlock(wait_mutex); inode_unlock(d_inode(wait));
dput(wait);
} }
} while (ret == -EAGAIN); } while (ret == -EAGAIN);