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authorAl Viro <viro@zeniv.linux.org.uk>2008-12-30 07:52:35 +0100
committerAl Viro <viro@zeniv.linux.org.uk>2009-01-01 00:07:43 +0100
commit41080b5a240113328c607f22b849f653373db0ce (patch)
treeaa8fd483c241140ebe73b6c71b370f4ad6a12251
parentnfsd/create race fixes, infrastructure (diff)
downloadlinux-41080b5a240113328c607f22b849f653373db0ce.tar.xz
linux-41080b5a240113328c607f22b849f653373db0ce.zip
nfsd race fixes: ext2
* make ext2_new_inode() put the inode into icache in locked state * do not unlock until the inode is fully set up; otherwise nfsd might pick it in half-baked state. * make sure that ext2_new_inode() does *not* lead to two inodes with the same inumber hashed at the same time; otherwise a bogus fhandle coming from nfsd might race with inode creation: nfsd: iget_locked() creates inode nfsd: try to read from disk, block on that. ext2_new_inode(): allocate inode with that inumber ext2_new_inode(): insert it into icache, set it up and dirty ext2_write_inode(): get the relevant part of inode table in cache, set the entry for our inode (and start writing to disk) nfsd: get CPU again, look into inode table, see nice and sane on-disk inode, set the in-core inode from it oops - we have two in-core inodes with the same inumber live in icache, both used for IO. Welcome to fs corruption... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/ext2/ialloc.c6
-rw-r--r--fs/ext2/namei.c15
2 files changed, 19 insertions, 2 deletions
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index 8d0add625870..c454d5db28a5 100644
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -585,7 +585,10 @@ got:
spin_lock(&sbi->s_next_gen_lock);
inode->i_generation = sbi->s_next_generation++;
spin_unlock(&sbi->s_next_gen_lock);
- insert_inode_hash(inode);
+ if (insert_inode_locked(inode) < 0) {
+ err = -EINVAL;
+ goto fail_drop;
+ }
if (DQUOT_ALLOC_INODE(inode)) {
err = -EDQUOT;
@@ -612,6 +615,7 @@ fail_drop:
DQUOT_DROP(inode);
inode->i_flags |= S_NOQUOTA;
inode->i_nlink = 0;
+ unlock_new_inode(inode);
iput(inode);
return ERR_PTR(err);
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index 2a747252ec12..90ea17998a73 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -41,9 +41,11 @@ static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
int err = ext2_add_link(dentry, inode);
if (!err) {
d_instantiate(dentry, inode);
+ unlock_new_inode(inode);
return 0;
}
inode_dec_link_count(inode);
+ unlock_new_inode(inode);
iput(inode);
return err;
}
@@ -170,6 +172,7 @@ out:
out_fail:
inode_dec_link_count(inode);
+ unlock_new_inode(inode);
iput (inode);
goto out;
}
@@ -178,6 +181,7 @@ static int ext2_link (struct dentry * old_dentry, struct inode * dir,
struct dentry *dentry)
{
struct inode *inode = old_dentry->d_inode;
+ int err;
if (inode->i_nlink >= EXT2_LINK_MAX)
return -EMLINK;
@@ -186,7 +190,14 @@ static int ext2_link (struct dentry * old_dentry, struct inode * dir,
inode_inc_link_count(inode);
atomic_inc(&inode->i_count);
- return ext2_add_nondir(dentry, inode);
+ err = ext2_add_link(dentry, inode);
+ if (!err) {
+ d_instantiate(dentry, inode);
+ return 0;
+ }
+ inode_dec_link_count(inode);
+ iput(inode);
+ return err;
}
static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
@@ -222,12 +233,14 @@ static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
goto out_fail;
d_instantiate(dentry, inode);
+ unlock_new_inode(inode);
out:
return err;
out_fail:
inode_dec_link_count(inode);
inode_dec_link_count(inode);
+ unlock_new_inode(inode);
iput(inode);
out_dir:
inode_dec_link_count(dir);