ext4: propagate errors from ext4_sb_bread() in ext4_xattr_block_cache_find()

In ext4_xattr_block_cache_find(), when ext4_sb_bread() returns an error,
we will either continue to find the next ea block or return NULL to try to
insert a new ea block. But whether ext4_sb_bread() returns -EIO or -ENOMEM,
the next operation is most likely to fail with the same error. So propagate
the error returned by ext4_sb_bread() to make ext4_xattr_block_set() fail
to reduce pointless operations.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240504075526.2254349-3-libaokun@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 3e9b088800b1b0112722abea28e95e07a50ea3d8..6460879b9fcbb35ddb40139659cd9fce080f83ce 100644 (file)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2028,8 +2028,13 @@ clone_block:
 
 inserted:
        if (!IS_LAST_ENTRY(s->first)) {
-               new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
-                                                    &ce);
+               new_bh = ext4_xattr_block_cache_find(inode, header(s->base), &ce);
+               if (IS_ERR(new_bh)) {
+                       error = PTR_ERR(new_bh);
+                       new_bh = NULL;
+                       goto cleanup;
+               }
+
                if (new_bh) {
                        /* We found an identical block in the cache. */
                        if (new_bh == bs->bh)
@@ -3094,8 +3099,8 @@ ext4_xattr_cmp(struct ext4_xattr_header *header1,
  *
  * Find an identical extended attribute block.
  *
- * Returns a pointer to the block found, or NULL if such a block was
- * not found or an error occurred.
+ * Returns a pointer to the block found, or NULL if such a block was not
+ * found, or an error pointer if an error occurred while reading ea block.
  */
 static struct buffer_head *
 ext4_xattr_block_cache_find(struct inode *inode,
@@ -3117,13 +3122,11 @@ ext4_xattr_block_cache_find(struct inode *inode,
 
                bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO);
                if (IS_ERR(bh)) {
-                       if (PTR_ERR(bh) == -ENOMEM) {
-                               mb_cache_entry_put(ea_block_cache, ce);
-                               return NULL;
-                       }
-                       bh = NULL;
-                       EXT4_ERROR_INODE(inode, "block %lu read error",
-                                        (unsigned long)ce->e_value);
+                       if (PTR_ERR(bh) != -ENOMEM)
+                               EXT4_ERROR_INODE(inode, "block %lu read error",
+                                                (unsigned long)ce->e_value);
+                       mb_cache_entry_put(ea_block_cache, ce);
+                       return bh;
                } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
                        *pce = ce;
                        return bh;