diff options
author | Miklos Szeredi <mszeredi@suse.cz> | 2013-09-05 11:44:42 +0200 |
---|---|---|
committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-09-05 16:23:53 -0400 |
commit | 5835f3390e35ae3da9add646a2ca2cc30b47370e (patch) | |
tree | 01bf2c9ddb37a08b4db112281b77fc1a97f7c537 /fs/fuse | |
parent | 6497d160f6abf8d1082ff1a4efd841118cb1fddd (diff) | |
download | linux-stable-5835f3390e35ae3da9add646a2ca2cc30b47370e.tar.gz linux-stable-5835f3390e35ae3da9add646a2ca2cc30b47370e.tar.bz2 linux-stable-5835f3390e35ae3da9add646a2ca2cc30b47370e.zip |
fuse: use d_materialise_unique()
Use d_materialise_unique() instead of d_splice_alias(). This allows dentry
subtrees to be moved to a new place if there moved, even if something is
referencing a dentry in the subtree (open fd, cwd, etc..).
This will also allow us to drop a subtree if it is found to be replaced by
something else. In this case the disconnected subtree can later be
reconnected to its new location.
d_materialise_unique() ensures that a directory entry only ever has one
alias. We keep fc->inst_mutex around the calls for d_materialise_unique()
on directories to prevent a race with mkdir "stealing" the inode.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/fuse')
-rw-r--r-- | fs/fuse/dir.c | 69 |
1 files changed, 26 insertions, 43 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 72a5d5b04494..131d14b604ef 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -267,26 +267,6 @@ int fuse_valid_type(int m) S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m); } -/* - * Add a directory inode to a dentry, ensuring that no other dentry - * refers to this inode. Called with fc->inst_mutex. - */ -static struct dentry *fuse_d_add_directory(struct dentry *entry, - struct inode *inode) -{ - struct dentry *alias = d_find_alias(inode); - if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) { - /* This tries to shrink the subtree below alias */ - fuse_invalidate_entry(alias); - dput(alias); - if (!hlist_empty(&inode->i_dentry)) - return ERR_PTR(-EBUSY); - } else { - dput(alias); - } - return d_splice_alias(inode, entry); -} - int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name, struct fuse_entry_out *outarg, struct inode **inode) { @@ -345,6 +325,24 @@ int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name, return err; } +static struct dentry *fuse_materialise_dentry(struct dentry *dentry, + struct inode *inode) +{ + struct dentry *newent; + + if (inode && S_ISDIR(inode->i_mode)) { + struct fuse_conn *fc = get_fuse_conn(inode); + + mutex_lock(&fc->inst_mutex); + newent = d_materialise_unique(dentry, inode); + mutex_unlock(&fc->inst_mutex); + } else { + newent = d_materialise_unique(dentry, inode); + } + + return newent; +} + static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry, unsigned int flags) { @@ -352,7 +350,6 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry, struct fuse_entry_out outarg; struct inode *inode; struct dentry *newent; - struct fuse_conn *fc = get_fuse_conn(dir); bool outarg_valid = true; err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name, @@ -368,16 +365,10 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry, if (inode && get_node_id(inode) == FUSE_ROOT_ID) goto out_iput; - if (inode && S_ISDIR(inode->i_mode)) { - mutex_lock(&fc->inst_mutex); - newent = fuse_d_add_directory(entry, inode); - mutex_unlock(&fc->inst_mutex); - err = PTR_ERR(newent); - if (IS_ERR(newent)) - goto out_iput; - } else { - newent = d_splice_alias(inode, entry); - } + newent = fuse_materialise_dentry(entry, inode); + err = PTR_ERR(newent); + if (IS_ERR(newent)) + goto out_err; entry = newent ? newent : entry; if (outarg_valid) @@ -1275,18 +1266,10 @@ static int fuse_direntplus_link(struct file *file, if (!inode) goto out; - if (S_ISDIR(inode->i_mode)) { - mutex_lock(&fc->inst_mutex); - alias = fuse_d_add_directory(dentry, inode); - mutex_unlock(&fc->inst_mutex); - err = PTR_ERR(alias); - if (IS_ERR(alias)) { - iput(inode); - goto out; - } - } else { - alias = d_splice_alias(inode, dentry); - } + alias = fuse_materialise_dentry(dentry, inode); + err = PTR_ERR(alias); + if (IS_ERR(alias)) + goto out; if (alias) { dput(dentry); |