ext4: add ext4_sb_bread() to disambiguate ENOMEM cases
Today, when sb_bread() returns NULL, this can either be because of an
I/O error or because the system failed to allocate the buffer. Since
it's an old interface, changing would require changing many call
sites.
So instead we create our own ext4_sb_bread(), which also allows us to
set the REQ_META flag.
Also fixed a problem in the xattr code where a NULL return in a
function could also mean that the xattr was not found, which could
lead to the wrong error getting returned to userspace.
Fixes: ac27a0ec112a ("ext4: initial copy of files from ext3")
Cc: stable@kernel.org # 2.6.19
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 7643d52..510c9bb 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -522,14 +522,13 @@
ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
name_index, name, buffer, (long)buffer_size);
- error = -ENODATA;
if (!EXT4_I(inode)->i_file_acl)
- goto cleanup;
+ return -ENODATA;
ea_idebug(inode, "reading block %llu",
(unsigned long long)EXT4_I(inode)->i_file_acl);
- bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
- if (!bh)
- goto cleanup;
+ bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
ea_bdebug(bh, "b_count=%d, refcount=%d",
atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
error = ext4_xattr_check_block(inode, bh);
@@ -696,26 +695,23 @@
ea_idebug(inode, "buffer=%p, buffer_size=%ld",
buffer, (long)buffer_size);
- error = 0;
if (!EXT4_I(inode)->i_file_acl)
- goto cleanup;
+ return 0;
ea_idebug(inode, "reading block %llu",
(unsigned long long)EXT4_I(inode)->i_file_acl);
- bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
- error = -EIO;
- if (!bh)
- goto cleanup;
+ bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+ if (IS_ERR(bh))
+ return PTR_ERR(bh);
ea_bdebug(bh, "b_count=%d, refcount=%d",
atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
error = ext4_xattr_check_block(inode, bh);
if (error)
goto cleanup;
ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), bh);
- error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
-
+ error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer,
+ buffer_size);
cleanup:
brelse(bh);
-
return error;
}
@@ -830,9 +826,9 @@
}
if (EXT4_I(inode)->i_file_acl) {
- bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
- if (!bh) {
- ret = -EIO;
+ bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+ if (IS_ERR(bh)) {
+ ret = PTR_ERR(bh);
goto out;
}
@@ -1821,16 +1817,15 @@
if (EXT4_I(inode)->i_file_acl) {
/* The inode already has an extended attribute block. */
- bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
- error = -EIO;
- if (!bs->bh)
- goto cleanup;
+ bs->bh = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+ if (IS_ERR(bs->bh))
+ return PTR_ERR(bs->bh);
ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
atomic_read(&(bs->bh->b_count)),
le32_to_cpu(BHDR(bs->bh)->h_refcount));
error = ext4_xattr_check_block(inode, bs->bh);
if (error)
- goto cleanup;
+ return error;
/* Find the named attribute. */
bs->s.base = BHDR(bs->bh);
bs->s.first = BFIRST(bs->bh);
@@ -1839,13 +1834,10 @@
error = xattr_find_entry(inode, &bs->s.here, bs->s.end,
i->name_index, i->name, 1);
if (error && error != -ENODATA)
- goto cleanup;
+ return error;
bs->s.not_found = error;
}
- error = 0;
-
-cleanup:
- return error;
+ return 0;
}
static int
@@ -2274,9 +2266,9 @@
if (!EXT4_I(inode)->i_file_acl)
return NULL;
- bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
- if (!bh)
- return ERR_PTR(-EIO);
+ bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+ if (IS_ERR(bh))
+ return bh;
error = ext4_xattr_check_block(inode, bh);
if (error) {
brelse(bh);
@@ -2746,10 +2738,11 @@
if (EXT4_I(inode)->i_file_acl) {
struct buffer_head *bh;
- bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
- error = -EIO;
- if (!bh)
+ bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+ if (IS_ERR(bh)) {
+ error = PTR_ERR(bh);
goto cleanup;
+ }
error = ext4_xattr_check_block(inode, bh);
if (error) {
brelse(bh);
@@ -2903,11 +2896,12 @@
}
if (EXT4_I(inode)->i_file_acl) {
- bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
- if (!bh) {
- EXT4_ERROR_INODE(inode, "block %llu read error",
- EXT4_I(inode)->i_file_acl);
- error = -EIO;
+ bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO);
+ if (IS_ERR(bh)) {
+ error = PTR_ERR(bh);
+ if (error == -EIO)
+ EXT4_ERROR_INODE(inode, "block %llu read error",
+ EXT4_I(inode)->i_file_acl);
goto cleanup;
}
error = ext4_xattr_check_block(inode, bh);
@@ -3060,8 +3054,10 @@
while (ce) {
struct buffer_head *bh;
- bh = sb_bread(inode->i_sb, ce->e_value);
- if (!bh) {
+ bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
+ if (IS_ERR(bh)) {
+ if (PTR_ERR(bh) == -ENOMEM)
+ return NULL;
EXT4_ERROR_INODE(inode, "block %lu read error",
(unsigned long)ce->e_value);
} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {