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ext4: fix ext4_swap_extents() error handling 

If ext4_ext_find_extent() returns an error, we have to clear path1 or
path2 or else we would end up trying to free an ERR_PTR, which would
be bad.

Also eliminate some redundant code and mark the error paths as unlikely()

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2014-08-31 15:03:14 -04:00
parent fcf6b1b729
commit 19008f6dfa
1 changed files with 29 additions and 33 deletions
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62
fs/ext4/extents.c
View File

@ -869,7 +869,7 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
if (!path) {
path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
GFP_NOFS);
if (!path)
if (unlikely(!path))
return ERR_PTR(-ENOMEM);
alloc = 1;
}
@ -889,7 +889,7 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
flags);
if (IS_ERR(bh)) {
if (unlikely(IS_ERR(bh))) {
ret = PTR_ERR(bh);
goto err;
}
@ -5545,10 +5545,10 @@ ext4_swap_extents(handle_t *handle, struct inode *inode1,
BUG_ON(!mutex_is_locked(&inode1->i_mutex));
*erp = ext4_es_remove_extent(inode1, lblk1, count);
if (*erp)
if (unlikely(*erp))
return 0;
*erp = ext4_es_remove_extent(inode2, lblk2, count);
if (*erp)
if (unlikely(*erp))
return 0;
while (count) {
@ -5558,20 +5558,24 @@ ext4_swap_extents(handle_t *handle, struct inode *inode1,
int split = 0;
path1 = ext4_ext_find_extent(inode1, lblk1, NULL, EXT4_EX_NOCACHE);
if (IS_ERR(path1)) {
if (unlikely(IS_ERR(path1))) {
*erp = PTR_ERR(path1);
break;
path1 = NULL;
finish:
count = 0;
goto repeat;
}
path2 = ext4_ext_find_extent(inode2, lblk2, NULL, EXT4_EX_NOCACHE);
if (IS_ERR(path2)) {
if (unlikely(IS_ERR(path2))) {
*erp = PTR_ERR(path2);
break;
path2 = NULL;
goto finish;
}
ex1 = path1[path1->p_depth].p_ext;
ex2 = path2[path2->p_depth].p_ext;
/* Do we have somthing to swap ? */
if (unlikely(!ex2 || !ex1))
break;
goto finish;
e1_blk = le32_to_cpu(ex1->ee_block);
e2_blk = le32_to_cpu(ex2->ee_block);
@ -5593,7 +5597,7 @@ ext4_swap_extents(handle_t *handle, struct inode *inode1,
next2 = e1_blk;
/* Do we have something to swap */
if (next1 == EXT_MAX_BLOCKS || next2 == EXT_MAX_BLOCKS)
break;
goto finish;
/* Move to the rightest boundary */
len = next1 - lblk1;
if (len < next2 - lblk2)
@ -5611,15 +5615,15 @@ ext4_swap_extents(handle_t *handle, struct inode *inode1,
split = 1;
*erp = ext4_force_split_extent_at(handle, inode1,
path1, lblk1, 0);
if (*erp)
break;
if (unlikely(*erp))
goto finish;
}
if (e2_blk < lblk2) {
split = 1;
*erp = ext4_force_split_extent_at(handle, inode2,
path2, lblk2, 0);
if (*erp)
break;
if (unlikely(*erp))
goto finish;
}
/* ext4_split_extent_at() may retult in leaf extent split,
* path must to be revalidated. */
@ -5637,15 +5641,15 @@ ext4_swap_extents(handle_t *handle, struct inode *inode1,
split = 1;
*erp = ext4_force_split_extent_at(handle, inode1,
path1, lblk1 + len, 0);
if (*erp)
break;
if (unlikely(*erp))
goto finish;
}
if (len != e2_len) {
split = 1;
*erp = ext4_force_split_extent_at(handle, inode2,
path2, lblk2 + len, 0);
if (*erp)
break;
goto finish;
}
/* ext4_split_extent_at() may retult in leaf extent split,
* path must to be revalidated. */
@ -5654,11 +5658,11 @@ ext4_swap_extents(handle_t *handle, struct inode *inode1,
BUG_ON(e2_len != e1_len);
*erp = ext4_ext_get_access(handle, inode1, path1 + path1->p_depth);
if (*erp)
break;
if (unlikely(*erp))
goto finish;
*erp = ext4_ext_get_access(handle, inode2, path2 + path2->p_depth);
if (*erp)
break;
if (unlikely(*erp))
goto finish;
/* Both extents are fully inside boundaries. Swap it now */
tmp_ex = *ex1;
@ -5675,8 +5679,8 @@ ext4_swap_extents(handle_t *handle, struct inode *inode1,
ext4_ext_try_to_merge(handle, inode1, path1, ex1);
*erp = ext4_ext_dirty(handle, inode2, path2 +
path2->p_depth);
if (*erp)
break;
if (unlikely(*erp))
goto finish;
*erp = ext4_ext_dirty(handle, inode1, path1 +
path1->p_depth);
/*
@ -5685,8 +5689,8 @@ ext4_swap_extents(handle_t *handle, struct inode *inode1,
* only due to journal error, so full transaction will be
* aborted anyway.
*/
if (*erp)
break;
if (unlikely(*erp))
goto finish;
lblk1 += len;
lblk2 += len;
replaced_count += len;
@ -5704,13 +5708,5 @@ ext4_swap_extents(handle_t *handle, struct inode *inode1,
path2 = NULL;
}
}
if (path1) {
ext4_ext_drop_refs(path1);
kfree(path1);
}
if (path2) {
ext4_ext_drop_refs(path2);
kfree(path2);
}
return replaced_count;
}