[PATCH 1/2] ext4: optimize ea_inode block expansion

Jun Nie
2022-12-30T11:00:00Z

Copy ea data from inode entry when expanding ea block if possible.
Then remove the ea entry if expansion success. Thus memcpy to a
temporary buffer may be avoided.

If the expansion fails, we do not need to recovery the removed ea
entry neither in this way.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
---
fs/ext4/xattr.c | 28 +++++++++++++++++-----------
1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 7decaaf27e82..235a517d9c17 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2551,9 +2551,8 @@ static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,

is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
- buffer = kvmalloc(value_size, GFP_NOFS);
b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS);
- if (!is || !bs || !buffer || !b_entry_name) {
+ if (!is || !bs || !b_entry_name) {
error = -ENOMEM;
goto out;
}
@@ -2565,12 +2564,18 @@ static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,

/* Save the entry name and the entry value */
if (entry->e_value_inum) {
+ buffer = kvmalloc(value_size, GFP_NOFS);
+ if (!buffer) {
+ error = -ENOMEM;
+ goto out;
+ }
+
error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
if (error)
goto out;
} else {
size_t value_offs = le16_to_cpu(entry->e_value_offs);
- memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
+ buffer = (void *)IFIRST(header) + value_offs;
}

memcpy(b_entry_name, entry->e_name, entry->e_name_len);
@@ -2585,25 +2590,26 @@ static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
if (error)
goto out;

- /* Remove the chosen entry from the inode */
- error = ext4_xattr_ibody_set(handle, inode, &i, is);
- if (error)
- goto out;
-
i.value = buffer;
i.value_len = value_size;
error = ext4_xattr_block_find(inode, &i, bs);
if (error)
goto out;

- /* Add entry which was removed from the inode into the block */
+ /* Move ea entry from the inode into the block */
error = ext4_xattr_block_set(handle, inode, &i, bs);
if (error)
goto out;
- error = 0;
+
+ /* Remove the chosen entry from the inode */
+ i.value = NULL;
+ i.value_len = 0;
+ error = ext4_xattr_ibody_set(handle, inode, &i, is);
+
out:
kfree(b_entry_name);
- kvfree(buffer);
+ if (entry->e_value_inum && buffer)
+ kvfree(buffer);
if (is)
brelse(is->iloc.bh);
if (bs)
--
2.34.1