reiserfs: simplify xattr internal file lookups/opens
The xattr file open/lookup code is needlessly complex. We can use vfs-level operations to perform the same work, and also simplify the locking constraints. The locking advantages will be exploited in future patches. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Mahoney
Linus Torvalds
parent
a72bdb1cd2
commit
6c17675e1e
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@ -44,100 +44,123 @@
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#include <net/checksum.h>
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#include <linux/smp_lock.h>
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#include <linux/stat.h>
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#include <linux/quotaops.h>
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#define FL_READONLY 128
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#define FL_DIR_SEM_HELD 256
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#define PRIVROOT_NAME ".reiserfs_priv"
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#define XAROOT_NAME "xattrs"
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/* Returns the dentry referring to the root of the extended attribute
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* directory tree. If it has already been retrieved, it is used. If it
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* hasn't been created and the flags indicate creation is allowed, we
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* attempt to create it. On error, we return a pointer-encoded error.
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*/
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static struct dentry *get_xa_root(struct super_block *sb, int flags)
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/* Helpers for inode ops. We do this so that we don't have all the VFS
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* overhead and also for proper i_mutex annotation.
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* dir->i_mutex must be held for all of them. */
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static int xattr_create(struct inode *dir, struct dentry *dentry, int mode)
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{
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struct dentry *privroot = dget(REISERFS_SB(sb)->priv_root);
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struct dentry *xaroot;
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/* This needs to be created at mount-time */
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if (!privroot)
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return ERR_PTR(-ENODATA);
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mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR);
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if (REISERFS_SB(sb)->xattr_root) {
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xaroot = dget(REISERFS_SB(sb)->xattr_root);
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goto out;
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}
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xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME));
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if (IS_ERR(xaroot)) {
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goto out;
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} else if (!xaroot->d_inode) {
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int err = -ENODATA;
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if (flags == 0 || flags & XATTR_CREATE)
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err = privroot->d_inode->i_op->mkdir(privroot->d_inode,
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xaroot, 0700);
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if (err) {
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dput(xaroot);
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xaroot = ERR_PTR(err);
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goto out;
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}
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}
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REISERFS_SB(sb)->xattr_root = dget(xaroot);
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out:
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mutex_unlock(&privroot->d_inode->i_mutex);
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dput(privroot);
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return xaroot;
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BUG_ON(!mutex_is_locked(&dir->i_mutex));
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DQUOT_INIT(dir);
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return dir->i_op->create(dir, dentry, mode, NULL);
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}
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static int xattr_mkdir(struct inode *dir, struct dentry *dentry, int mode)
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{
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BUG_ON(!mutex_is_locked(&dir->i_mutex));
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DQUOT_INIT(dir);
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return dir->i_op->mkdir(dir, dentry, mode);
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}
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/* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr
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* mutation ops aren't called during rename or splace, which are the
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* only other users of I_MUTEX_CHILD. It violates the ordering, but that's
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* better than allocating another subclass just for this code. */
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static int xattr_unlink(struct inode *dir, struct dentry *dentry)
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{
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int error;
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BUG_ON(!mutex_is_locked(&dir->i_mutex));
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DQUOT_INIT(dir);
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mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
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error = dir->i_op->unlink(dir, dentry);
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mutex_unlock(&dentry->d_inode->i_mutex);
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if (!error)
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d_delete(dentry);
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return error;
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}
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static int xattr_rmdir(struct inode *dir, struct dentry *dentry)
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{
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int error;
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BUG_ON(!mutex_is_locked(&dir->i_mutex));
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DQUOT_INIT(dir);
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mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
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dentry_unhash(dentry);
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error = dir->i_op->rmdir(dir, dentry);
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if (!error)
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dentry->d_inode->i_flags |= S_DEAD;
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mutex_unlock(&dentry->d_inode->i_mutex);
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if (!error)
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d_delete(dentry);
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dput(dentry);
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return error;
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}
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#define xattr_may_create(flags) (!flags || flags & XATTR_CREATE)
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/* Returns and possibly creates the xattr dir. */
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static struct dentry *lookup_or_create_dir(struct dentry *parent,
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const char *name, int flags)
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{
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struct dentry *dentry;
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BUG_ON(!parent);
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dentry = lookup_one_len(name, parent, strlen(name));
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if (IS_ERR(dentry))
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return dentry;
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else if (!dentry->d_inode) {
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int err = -ENODATA;
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if (xattr_may_create(flags)) {
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mutex_lock_nested(&parent->d_inode->i_mutex,
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I_MUTEX_XATTR);
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err = xattr_mkdir(parent->d_inode, dentry, 0700);
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mutex_unlock(&parent->d_inode->i_mutex);
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}
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if (err) {
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dput(dentry);
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dentry = ERR_PTR(err);
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}
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}
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return dentry;
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}
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static struct dentry *open_xa_root(struct super_block *sb, int flags)
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{
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struct dentry *privroot = REISERFS_SB(sb)->priv_root;
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if (!privroot)
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return ERR_PTR(-ENODATA);
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return lookup_or_create_dir(privroot, XAROOT_NAME, flags);
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}
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/* Opens the directory corresponding to the inode's extended attribute store.
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* If flags allow, the tree to the directory may be created. If creation is
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* prohibited, -ENODATA is returned. */
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static struct dentry *open_xa_dir(const struct inode *inode, int flags)
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{
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struct dentry *xaroot, *xadir;
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char namebuf[17];
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xaroot = get_xa_root(inode->i_sb, flags);
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xaroot = open_xa_root(inode->i_sb, flags);
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if (IS_ERR(xaroot))
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return xaroot;
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/* ok, we have xaroot open */
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snprintf(namebuf, sizeof(namebuf), "%X.%X",
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le32_to_cpu(INODE_PKEY(inode)->k_objectid),
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inode->i_generation);
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xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
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if (IS_ERR(xadir)) {
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dput(xaroot);
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return xadir;
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}
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if (!xadir->d_inode) {
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int err;
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if (flags == 0 || flags & XATTR_CREATE) {
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/* Although there is nothing else trying to create this directory,
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* another directory with the same hash may be created, so we need
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* to protect against that */
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err =
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xaroot->d_inode->i_op->mkdir(xaroot->d_inode, xadir,
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0700);
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if (err) {
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dput(xaroot);
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dput(xadir);
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return ERR_PTR(err);
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}
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}
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if (!xadir->d_inode) {
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dput(xaroot);
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dput(xadir);
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return ERR_PTR(-ENODATA);
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}
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}
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xadir = lookup_or_create_dir(xaroot, namebuf, flags);
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dput(xaroot);
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return xadir;
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}
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/*
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@ -302,13 +325,11 @@ static
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int xattr_readdir(struct inode *inode, filldir_t filler, void *buf)
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{
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int res = -ENOENT;
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mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR);
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if (!IS_DEADDIR(inode)) {
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lock_kernel();
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res = __xattr_readdir(inode, buf, filler);
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unlock_kernel();
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}
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mutex_unlock(&inode->i_mutex);
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return res;
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}
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@ -345,9 +366,7 @@ __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen)
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return -EIO;
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}
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err = dir->i_op->unlink(dir, dentry);
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if (!err)
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d_delete(dentry);
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err = xattr_unlink(dir, dentry);
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out_file:
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dput(dentry);
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@ -381,7 +400,7 @@ int reiserfs_delete_xattrs(struct inode *inode)
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return 0;
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reiserfs_read_lock_xattrs(inode->i_sb);
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dir = open_xa_dir(inode, FL_READONLY);
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dir = open_xa_dir(inode, XATTR_REPLACE);
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reiserfs_read_unlock_xattrs(inode->i_sb);
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if (IS_ERR(dir)) {
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err = PTR_ERR(dir);
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@ -391,25 +410,25 @@ int reiserfs_delete_xattrs(struct inode *inode)
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return 0;
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}
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lock_kernel();
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mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR);
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err = xattr_readdir(dir->d_inode, reiserfs_delete_xattrs_filler, dir);
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if (err) {
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unlock_kernel();
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mutex_unlock(&dir->d_inode->i_mutex);
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if (err)
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goto out_dir;
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}
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/* Leftovers besides . and .. -- that's not good. */
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if (dir->d_inode->i_nlink <= 2) {
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root = get_xa_root(inode->i_sb, XATTR_REPLACE);
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root = open_xa_root(inode->i_sb, XATTR_REPLACE);
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reiserfs_write_lock_xattrs(inode->i_sb);
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err = vfs_rmdir(root->d_inode, dir);
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mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_XATTR);
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err = xattr_rmdir(root->d_inode, dir);
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mutex_unlock(&root->d_inode->i_mutex);
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reiserfs_write_unlock_xattrs(inode->i_sb);
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dput(root);
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} else {
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reiserfs_warning(inode->i_sb, "jdm-20006",
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"Couldn't remove all entries in directory");
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}
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unlock_kernel();
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out_dir:
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dput(dir);
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@ -445,8 +464,11 @@ reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen,
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return -ENODATA;
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}
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if (!S_ISDIR(xafile->d_inode->i_mode))
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if (!S_ISDIR(xafile->d_inode->i_mode)) {
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mutex_lock_nested(&xafile->d_inode->i_mutex, I_MUTEX_CHILD);
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err = notify_change(xafile, attrs);
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mutex_unlock(&xafile->d_inode->i_mutex);
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}
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dput(xafile);
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return err;
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@ -464,38 +486,31 @@ int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
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return 0;
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reiserfs_read_lock_xattrs(inode->i_sb);
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dir = open_xa_dir(inode, FL_READONLY);
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dir = open_xa_dir(inode, XATTR_REPLACE);
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reiserfs_read_unlock_xattrs(inode->i_sb);
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if (IS_ERR(dir)) {
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if (PTR_ERR(dir) != -ENODATA)
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err = PTR_ERR(dir);
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goto out;
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} else if (!dir->d_inode) {
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dput(dir);
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goto out;
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}
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lock_kernel();
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} else if (!dir->d_inode)
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goto out_dir;
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attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME);
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buf.xadir = dir;
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buf.attrs = attrs;
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buf.inode = inode;
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mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR);
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err = xattr_readdir(dir->d_inode, reiserfs_chown_xattrs_filler, &buf);
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if (err) {
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unlock_kernel();
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goto out_dir;
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}
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err = notify_change(dir, attrs);
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unlock_kernel();
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if (!err)
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err = notify_change(dir, attrs);
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mutex_unlock(&dir->d_inode->i_mutex);
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attrs->ia_valid = ia_valid;
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out_dir:
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dput(dir);
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out:
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attrs->ia_valid = ia_valid;
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return err;
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}
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@ -513,47 +528,35 @@ static struct dentry *get_xa_file_dentry(const struct inode *inode,
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int err = 0;
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xadir = open_xa_dir(inode, flags);
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if (IS_ERR(xadir)) {
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if (IS_ERR(xadir))
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return ERR_CAST(xadir);
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} else if (xadir && !xadir->d_inode) {
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dput(xadir);
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return ERR_PTR(-ENODATA);
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}
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xafile = lookup_one_len(name, xadir, strlen(name));
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if (IS_ERR(xafile)) {
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dput(xadir);
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return ERR_CAST(xafile);
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}
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if (xafile->d_inode) { /* file exists */
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if (flags & XATTR_CREATE) {
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err = -EEXIST;
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dput(xafile);
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goto out;
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}
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} else if (flags & XATTR_REPLACE || flags & FL_READONLY) {
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err = PTR_ERR(xafile);
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goto out;
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} else {
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/* inode->i_mutex is down, so nothing else can try to create
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* the same xattr */
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err = xadir->d_inode->i_op->create(xadir->d_inode, xafile,
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0700 | S_IFREG, NULL);
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}
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if (err) {
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dput(xafile);
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goto out;
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if (xafile->d_inode && (flags & XATTR_CREATE))
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err = -EEXIST;
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if (!xafile->d_inode) {
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err = -ENODATA;
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if (xattr_may_create(flags)) {
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mutex_lock_nested(&xadir->d_inode->i_mutex,
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I_MUTEX_XATTR);
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err = xattr_create(xadir->d_inode, xafile,
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0700|S_IFREG);
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mutex_unlock(&xadir->d_inode->i_mutex);
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}
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}
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if (err)
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dput(xafile);
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out:
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dput(xadir);
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if (err)
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xafile = ERR_PTR(err);
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else if (!xafile->d_inode) {
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dput(xafile);
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xafile = ERR_PTR(-ENODATA);
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}
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return ERR_PTR(err);
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return xafile;
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}
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@ -633,6 +636,7 @@ reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer,
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newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
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mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR);
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err = notify_change(dentry, &newattrs);
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mutex_unlock(&dentry->d_inode->i_mutex);
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if (err)
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goto out_filp;
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@ -692,7 +696,6 @@ reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer,
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}
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out_filp:
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mutex_unlock(&dentry->d_inode->i_mutex);
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dput(dentry);
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out:
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@ -722,7 +725,7 @@ reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer,
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if (get_inode_sd_version(inode) == STAT_DATA_V1)
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return -EOPNOTSUPP;
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dentry = get_xa_file_dentry(inode, name, FL_READONLY);
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dentry = get_xa_file_dentry(inode, name, XATTR_REPLACE);
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if (IS_ERR(dentry)) {
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err = PTR_ERR(dentry);
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goto out;
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@ -806,13 +809,15 @@ int reiserfs_xattr_del(struct inode *inode, const char *name)
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struct dentry *dir;
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int err;
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dir = open_xa_dir(inode, FL_READONLY);
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dir = open_xa_dir(inode, XATTR_REPLACE);
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if (IS_ERR(dir)) {
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err = PTR_ERR(dir);
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goto out;
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}
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mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR);
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err = __reiserfs_xattr_del(dir, name, strlen(name));
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mutex_unlock(&dir->d_inode->i_mutex);
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dput(dir);
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if (!err) {
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@ -826,6 +831,7 @@ int reiserfs_xattr_del(struct inode *inode, const char *name)
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/* Actual operations that are exported to VFS-land */
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static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char *);
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/*
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* Inode operation getxattr()
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* Preliminary locking: we down dentry->d_inode->i_mutex
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@ -978,7 +984,7 @@ ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
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reiserfs_read_lock_xattr_i(dentry->d_inode);
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reiserfs_read_lock_xattrs(dentry->d_sb);
|
||||
dir = open_xa_dir(dentry->d_inode, FL_READONLY);
|
||||
dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE);
|
||||
reiserfs_read_unlock_xattrs(dentry->d_sb);
|
||||
if (IS_ERR(dir)) {
|
||||
err = PTR_ERR(dir);
|
||||
|
|
@ -994,7 +1000,9 @@ ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
|
|||
|
||||
REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir;
|
||||
|
||||
mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR);
|
||||
err = xattr_readdir(dir->d_inode, reiserfs_listxattr_filler, &buf);
|
||||
mutex_unlock(&dir->d_inode->i_mutex);
|
||||
if (err)
|
||||
goto out_dir;
|
||||
|
||||
|
|
@ -1146,7 +1154,7 @@ static int create_privroot(struct dentry *dentry)
|
|||
int err;
|
||||
struct inode *inode = dentry->d_parent->d_inode;
|
||||
mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR);
|
||||
err = inode->i_op->mkdir(inode, dentry, 0700);
|
||||
err = xattr_mkdir(inode, dentry, 0700);
|
||||
mutex_unlock(&inode->i_mutex);
|
||||
if (err) {
|
||||
dput(dentry);
|
||||
|
|
|
|||
Loading…
Reference in New Issue