xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

reiserfs: eliminate per-super xattr lock

Browse Source 
With the switch to using inode->i_mutex locking during lookups/creation
in the xattr root, the per-super xattr lock is no longer needed.

This patch removes it.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Mahoney
2009-03-30 14:02:35 -04:00
committed by Linus Torvalds
parent 6c17675e1e
commit d984561b32
8 changed files with 74 additions and 151 deletions
Download Patch File Download Diff File Expand all files Collapse all files

70
fs/reiserfs/xattr.c
View File

@@ -27,6 +27,12 @@
* these are special cases for filesystem ACLs, they are interpreted by the
* kernel, in addition, they are negatively and positively cached and attached
* to the inode so that unnecessary lookups are avoided.
*
* Locking works like so:
* The xattr root (/.reiserfs_priv/xattrs) is protected by its i_mutex.
* The xattr dir (/.reiserfs_priv/xattrs/<oid>.<gen>) is protected by
* inode->xattr_sem.
* The xattrs themselves are likewise protected by the xattr_sem.
*/
#include <linux/reiserfs_fs.h>
@@ -392,16 +398,17 @@ reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen,
/* This is called w/ inode->i_mutex downed */
int reiserfs_delete_xattrs(struct inode *inode)
{
struct dentry *dir, *root;
int err = 0;
struct dentry *dir, *root;
struct reiserfs_transaction_handle th;
int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 +
4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb);
/* Skip out, an xattr has no xattrs associated with it */
if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1)
return 0;
reiserfs_read_lock_xattrs(inode->i_sb);
dir = open_xa_dir(inode, XATTR_REPLACE);
reiserfs_read_unlock_xattrs(inode->i_sb);
if (IS_ERR(dir)) {
err = PTR_ERR(dir);
goto out;
@@ -416,18 +423,26 @@ int reiserfs_delete_xattrs(struct inode *inode)
if (err)
goto out_dir;
/* Leftovers besides . and .. -- that's not good. */
if (dir->d_inode->i_nlink <= 2) {
root = open_xa_root(inode->i_sb, XATTR_REPLACE);
reiserfs_write_lock_xattrs(inode->i_sb);
/* We start a transaction here to avoid a ABBA situation
* between the xattr root's i_mutex and the journal lock.
* Inode creation will inherit an ACL, which requires a
* lookup. The lookup locks the xattr root i_mutex with a
* transaction open. Inode deletion takes teh xattr root
* i_mutex to delete the directory and then starts a
* transaction inside it. Boom. This doesn't incur much
* additional overhead since the reiserfs_rmdir transaction
* will just nest inside the outer transaction. */
err = journal_begin(&th, inode->i_sb, blocks);
if (!err) {
int jerror;
root = dget(dir->d_parent);
mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_XATTR);
err = xattr_rmdir(root->d_inode, dir);
jerror = journal_end(&th, inode->i_sb, blocks);
mutex_unlock(&root->d_inode->i_mutex);
reiserfs_write_unlock_xattrs(inode->i_sb);
dput(root);
} else {
reiserfs_warning(inode->i_sb, "jdm-20006",
"Couldn't remove all entries in directory");
err = jerror ?: err;
}
out_dir:
@@ -437,6 +452,9 @@ out:
if (!err)
REISERFS_I(inode)->i_flags =
REISERFS_I(inode)->i_flags & ~i_has_xattr_dir;
else
reiserfs_warning(inode->i_sb, "jdm-20004",
"Couldn't remove all xattrs (%d)\n", err);
return err;
}
@@ -485,9 +503,7 @@ int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1)
return 0;
reiserfs_read_lock_xattrs(inode->i_sb);
dir = open_xa_dir(inode, XATTR_REPLACE);
reiserfs_read_unlock_xattrs(inode->i_sb);
if (IS_ERR(dir)) {
if (PTR_ERR(dir) != -ENODATA)
err = PTR_ERR(dir);
@@ -731,6 +747,11 @@ reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer,
goto out;
}
/* protect against concurrent access. xattrs are backed by
* regular files, but they're not regular files. The updates
* must be atomic from the perspective of the user. */
mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR);
isize = i_size_read(dentry->d_inode);
REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
@@ -798,6 +819,7 @@ reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer,
}
out_dput:
mutex_unlock(&dentry->d_inode->i_mutex);
dput(dentry);
out:
@@ -834,7 +856,6 @@ int reiserfs_xattr_del(struct inode *inode, const char *name)
static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char *);
/*
* Inode operation getxattr()
* Preliminary locking: we down dentry->d_inode->i_mutex
*/
ssize_t
reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer,
@@ -848,9 +869,7 @@ reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer,
return -EOPNOTSUPP;
reiserfs_read_lock_xattr_i(dentry->d_inode);
reiserfs_read_lock_xattrs(dentry->d_sb);
err = xah->get(dentry->d_inode, name, buffer, size);
reiserfs_read_unlock_xattrs(dentry->d_sb);
reiserfs_read_unlock_xattr_i(dentry->d_inode);
return err;
}
@@ -866,23 +885,13 @@ reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value,
{
struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name);
int err;
int lock;
if (!xah || !reiserfs_xattrs(dentry->d_sb) ||
get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1)
return -EOPNOTSUPP;
reiserfs_write_lock_xattr_i(dentry->d_inode);
lock = !has_xattr_dir(dentry->d_inode);
if (lock)
reiserfs_write_lock_xattrs(dentry->d_sb);
else
reiserfs_read_lock_xattrs(dentry->d_sb);
err = xah->set(dentry->d_inode, name, value, size, flags);
if (lock)
reiserfs_write_unlock_xattrs(dentry->d_sb);
else
reiserfs_read_unlock_xattrs(dentry->d_sb);
reiserfs_write_unlock_xattr_i(dentry->d_inode);
return err;
}
@@ -902,8 +911,6 @@ int reiserfs_removexattr(struct dentry *dentry, const char *name)
return -EOPNOTSUPP;
reiserfs_write_lock_xattr_i(dentry->d_inode);
reiserfs_read_lock_xattrs(dentry->d_sb);
/* Deletion pre-operation */
if (xah->del) {
err = xah->del(dentry->d_inode, name);
@@ -917,7 +924,6 @@ int reiserfs_removexattr(struct dentry *dentry, const char *name)
mark_inode_dirty(dentry->d_inode);
out:
reiserfs_read_unlock_xattrs(dentry->d_sb);
reiserfs_write_unlock_xattr_i(dentry->d_inode);
return err;
}
@@ -966,8 +972,6 @@ reiserfs_listxattr_filler(void *buf, const char *name, int namelen,
/*
* Inode operation listxattr()
*
* Preliminary locking: we down dentry->d_inode->i_mutex
*/
ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
{
@@ -983,9 +987,7 @@ ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
return -EOPNOTSUPP;
reiserfs_read_lock_xattr_i(dentry->d_inode);
reiserfs_read_lock_xattrs(dentry->d_sb);
dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE);
reiserfs_read_unlock_xattrs(dentry->d_sb);
if (IS_ERR(dir)) {
err = PTR_ERR(dir);
if (err == -ENODATA)
@@ -1114,11 +1116,9 @@ static int reiserfs_check_acl(struct inode *inode, int mask)
int error = -EAGAIN; /* do regular unix permission checks by default */
reiserfs_read_lock_xattr_i(inode);
reiserfs_read_lock_xattrs(inode->i_sb);
acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
reiserfs_read_unlock_xattrs(inode->i_sb);
reiserfs_read_unlock_xattr_i(inode);
if (acl) {