ext4: propagate errors up to ext4_find_entry()'s callers
If we run into some kind of error, such as ENOMEM, while calling
ext4_getblk() or ext4_dx_find_entry(), we need to make sure this error
gets propagated up to ext4_find_entry() and then to its callers. This
way, transient errors such as ENOMEM can get propagated to the VFS.
This is important so that the system calls return the appropriate
error, and also so that in the case of ext4_lookup(), we return an
error instead of a NULL inode, since that will result in a negative
dentry cache entry that will stick around long past the OOM condition
which caused a transient ENOMEM error.
Google-Bug-Id: #17142205
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index b147a67..ae7088b 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1227,7 +1227,7 @@
buffer */
int num = 0;
ext4_lblk_t nblocks;
- int i, err;
+ int i, err = 0;
int namelen;
*res_dir = NULL;
@@ -1264,7 +1264,11 @@
* return. Otherwise, fall back to doing a search the
* old fashioned way.
*/
- if (bh || (err != ERR_BAD_DX_DIR))
+ if (err == -ENOENT)
+ return NULL;
+ if (err && err != ERR_BAD_DX_DIR)
+ return ERR_PTR(err);
+ if (bh)
return bh;
dxtrace(printk(KERN_DEBUG "ext4_find_entry: dx failed, "
"falling back\n"));
@@ -1295,6 +1299,11 @@
}
num++;
bh = ext4_getblk(NULL, dir, b++, 0, &err);
+ if (unlikely(err)) {
+ if (ra_max == 0)
+ return ERR_PTR(err);
+ break;
+ }
bh_use[ra_max] = bh;
if (bh)
ll_rw_block(READ | REQ_META | REQ_PRIO,
@@ -1417,6 +1426,8 @@
return ERR_PTR(-ENAMETOOLONG);
bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
+ if (IS_ERR(bh))
+ return (struct dentry *) bh;
inode = NULL;
if (bh) {
__u32 ino = le32_to_cpu(de->inode);
@@ -1450,6 +1461,8 @@
struct buffer_head *bh;
bh = ext4_find_entry(child->d_inode, &dotdot, &de, NULL);
+ if (IS_ERR(bh))
+ return (struct dentry *) bh;
if (!bh)
return ERR_PTR(-ENOENT);
ino = le32_to_cpu(de->inode);
@@ -2727,6 +2740,8 @@
retval = -ENOENT;
bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
if (!bh)
goto end_rmdir;
@@ -2794,6 +2809,8 @@
retval = -ENOENT;
bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
if (!bh)
goto end_unlink;
@@ -3121,6 +3138,8 @@
struct ext4_dir_entry_2 *de;
bh = ext4_find_entry(dir, d_name, &de, NULL);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
if (bh) {
retval = ext4_delete_entry(handle, dir, de, bh);
brelse(bh);
@@ -3202,6 +3221,8 @@
dquot_initialize(new.inode);
old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
+ if (IS_ERR(old.bh))
+ return PTR_ERR(old.bh);
/*
* Check for inode number is _not_ due to possible IO errors.
* We might rmdir the source, keep it as pwd of some process
@@ -3214,6 +3235,10 @@
new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
&new.de, &new.inlined);
+ if (IS_ERR(new.bh)) {
+ retval = PTR_ERR(new.bh);
+ goto end_rename;
+ }
if (new.bh) {
if (!new.inode) {
brelse(new.bh);
@@ -3330,6 +3355,8 @@
old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
&old.de, &old.inlined);
+ if (IS_ERR(old.bh))
+ return PTR_ERR(old.bh);
/*
* Check for inode number is _not_ due to possible IO errors.
* We might rmdir the source, keep it as pwd of some process
@@ -3342,6 +3369,10 @@
new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
&new.de, &new.inlined);
+ if (IS_ERR(new.bh)) {
+ retval = PTR_ERR(new.bh);
+ goto end_rename;
+ }
/* RENAME_EXCHANGE case: old *and* new must both exist */
if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)