Re: [PATCH 2/2] ext4: propagate errors from ext4_sb_bread() in ext4_xattr_block_cache_find()

From: Jan Kara
Date: Mon May 06 2024 - 16:40:53 EST


On Sat 04-05-24 15:55:26, libaokun@xxxxxxxxxxxxxxx wrote:
> From: Baokun Li <libaokun1@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

Honza

> ---
> fs/ext4/xattr.c | 25 ++++++++++++++-----------
> 1 file changed, 14 insertions(+), 11 deletions(-)
>
> diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
> index 9fdd13422073..11742e1f16d7 100644
> --- a/fs/ext4/xattr.c
> +++ b/fs/ext4/xattr.c
> @@ -2059,8 +2059,13 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
>
> 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)
> @@ -3090,8 +3095,8 @@ 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,
> @@ -3113,13 +3118,11 @@ 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;
> --
> 2.39.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR