The "if (!buffer_uptodate(bh))" hunk covered almost the whole code after
getting buffer in __ext4_get_inode_loc() which seems unnecessary, remove
it and switch to check ext4_buffer_uptodate(), it simplify code and make
it more readable.
Signed-off-by: Zhang Yi <[email protected]>
---
fs/ext4/inode.c | 162 +++++++++++++++++++++++-------------------------
1 file changed, 78 insertions(+), 84 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index eb2526a35254..eae1b2d0b550 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4330,99 +4330,93 @@ static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
bh = sb_getblk(sb, block);
if (unlikely(!bh))
return -ENOMEM;
- if (!buffer_uptodate(bh)) {
- lock_buffer(bh);
-
- if (ext4_buffer_uptodate(bh)) {
- /* someone brought it uptodate while we waited */
- unlock_buffer(bh);
- goto has_buffer;
- }
+ if (ext4_buffer_uptodate(bh))
+ goto has_buffer;
- /*
- * If we have all information of the inode in memory and this
- * is the only valid inode in the block, we need not read the
- * block.
- */
- if (in_mem) {
- struct buffer_head *bitmap_bh;
- int i, start;
+ lock_buffer(bh);
+ /*
+ * If we have all information of the inode in memory and this
+ * is the only valid inode in the block, we need not read the
+ * block.
+ */
+ if (in_mem) {
+ struct buffer_head *bitmap_bh;
+ int i, start;
- start = inode_offset & ~(inodes_per_block - 1);
+ start = inode_offset & ~(inodes_per_block - 1);
- /* Is the inode bitmap in cache? */
- bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
- if (unlikely(!bitmap_bh))
- goto make_io;
+ /* Is the inode bitmap in cache? */
+ bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
+ if (unlikely(!bitmap_bh))
+ goto make_io;
- /*
- * If the inode bitmap isn't in cache then the
- * optimisation may end up performing two reads instead
- * of one, so skip it.
- */
- if (!buffer_uptodate(bitmap_bh)) {
- brelse(bitmap_bh);
- goto make_io;
- }
- for (i = start; i < start + inodes_per_block; i++) {
- if (i == inode_offset)
- continue;
- if (ext4_test_bit(i, bitmap_bh->b_data))
- break;
- }
+ /*
+ * If the inode bitmap isn't in cache then the
+ * optimisation may end up performing two reads instead
+ * of one, so skip it.
+ */
+ if (!buffer_uptodate(bitmap_bh)) {
brelse(bitmap_bh);
- if (i == start + inodes_per_block) {
- /* all other inodes are free, so skip I/O */
- memset(bh->b_data, 0, bh->b_size);
- set_buffer_uptodate(bh);
- unlock_buffer(bh);
- goto has_buffer;
- }
+ goto make_io;
+ }
+ for (i = start; i < start + inodes_per_block; i++) {
+ if (i == inode_offset)
+ continue;
+ if (ext4_test_bit(i, bitmap_bh->b_data))
+ break;
}
+ brelse(bitmap_bh);
+ if (i == start + inodes_per_block) {
+ /* all other inodes are free, so skip I/O */
+ memset(bh->b_data, 0, bh->b_size);
+ set_buffer_uptodate(bh);
+ unlock_buffer(bh);
+ goto has_buffer;
+ }
+ }
make_io:
- /*
- * If we need to do any I/O, try to pre-readahead extra
- * blocks from the inode table.
- */
- blk_start_plug(&plug);
- if (EXT4_SB(sb)->s_inode_readahead_blks) {
- ext4_fsblk_t b, end, table;
- unsigned num;
- __u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
-
- table = ext4_inode_table(sb, gdp);
- /* s_inode_readahead_blks is always a power of 2 */
- b = block & ~((ext4_fsblk_t) ra_blks - 1);
- if (table > b)
- b = table;
- end = b + ra_blks;
- num = EXT4_INODES_PER_GROUP(sb);
- if (ext4_has_group_desc_csum(sb))
- num -= ext4_itable_unused_count(sb, gdp);
- table += num / inodes_per_block;
- if (end > table)
- end = table;
- while (b <= end)
- ext4_sb_breadahead_unmovable(sb, b++);
- }
+ /*
+ * If we need to do any I/O, try to pre-readahead extra
+ * blocks from the inode table.
+ */
+ blk_start_plug(&plug);
+ if (EXT4_SB(sb)->s_inode_readahead_blks) {
+ ext4_fsblk_t b, end, table;
+ unsigned num;
+ __u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
+
+ table = ext4_inode_table(sb, gdp);
+ /* s_inode_readahead_blks is always a power of 2 */
+ b = block & ~((ext4_fsblk_t) ra_blks - 1);
+ if (table > b)
+ b = table;
+ end = b + ra_blks;
+ num = EXT4_INODES_PER_GROUP(sb);
+ if (ext4_has_group_desc_csum(sb))
+ num -= ext4_itable_unused_count(sb, gdp);
+ table += num / inodes_per_block;
+ if (end > table)
+ end = table;
+ while (b <= end)
+ ext4_sb_breadahead_unmovable(sb, b++);
+ }
- /*
- * There are other valid inodes in the buffer, this inode
- * has in-inode xattrs, or we don't have this inode in memory.
- * Read the block from disk.
- */
- trace_ext4_load_inode(sb, ino);
- ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
- blk_finish_plug(&plug);
- wait_on_buffer(bh);
- ext4_simulate_fail_bh(sb, bh, EXT4_SIM_INODE_EIO);
- if (!buffer_uptodate(bh)) {
- if (ret_block)
- *ret_block = block;
- brelse(bh);
- return -EIO;
- }
+ /*
+ * There are other valid inodes in the buffer, this inode
+ * has in-inode xattrs, or we don't have this inode in memory.
+ * Read the block from disk.
+ */
+ trace_ext4_load_inode(sb, ino);
+ ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
+ blk_finish_plug(&plug);
+ wait_on_buffer(bh);
+ ext4_simulate_fail_bh(sb, bh, EXT4_SIM_INODE_EIO);
+ if (!buffer_uptodate(bh)) {
+ if (ret_block)
+ *ret_block = block;
+ brelse(bh);
+ return -EIO;
}
has_buffer:
iloc->bh = bh;
--
2.31.1
On Tue 10-08-21 22:27:21, Zhang Yi wrote:
> The "if (!buffer_uptodate(bh))" hunk covered almost the whole code after
> getting buffer in __ext4_get_inode_loc() which seems unnecessary, remove
> it and switch to check ext4_buffer_uptodate(), it simplify code and make
> it more readable.
>
> Signed-off-by: Zhang Yi <[email protected]>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <[email protected]>
Honza
> ---
> fs/ext4/inode.c | 162 +++++++++++++++++++++++-------------------------
> 1 file changed, 78 insertions(+), 84 deletions(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index eb2526a35254..eae1b2d0b550 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4330,99 +4330,93 @@ static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
> bh = sb_getblk(sb, block);
> if (unlikely(!bh))
> return -ENOMEM;
> - if (!buffer_uptodate(bh)) {
> - lock_buffer(bh);
> -
> - if (ext4_buffer_uptodate(bh)) {
> - /* someone brought it uptodate while we waited */
> - unlock_buffer(bh);
> - goto has_buffer;
> - }
> + if (ext4_buffer_uptodate(bh))
> + goto has_buffer;
>
> - /*
> - * If we have all information of the inode in memory and this
> - * is the only valid inode in the block, we need not read the
> - * block.
> - */
> - if (in_mem) {
> - struct buffer_head *bitmap_bh;
> - int i, start;
> + lock_buffer(bh);
> + /*
> + * If we have all information of the inode in memory and this
> + * is the only valid inode in the block, we need not read the
> + * block.
> + */
> + if (in_mem) {
> + struct buffer_head *bitmap_bh;
> + int i, start;
>
> - start = inode_offset & ~(inodes_per_block - 1);
> + start = inode_offset & ~(inodes_per_block - 1);
>
> - /* Is the inode bitmap in cache? */
> - bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
> - if (unlikely(!bitmap_bh))
> - goto make_io;
> + /* Is the inode bitmap in cache? */
> + bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
> + if (unlikely(!bitmap_bh))
> + goto make_io;
>
> - /*
> - * If the inode bitmap isn't in cache then the
> - * optimisation may end up performing two reads instead
> - * of one, so skip it.
> - */
> - if (!buffer_uptodate(bitmap_bh)) {
> - brelse(bitmap_bh);
> - goto make_io;
> - }
> - for (i = start; i < start + inodes_per_block; i++) {
> - if (i == inode_offset)
> - continue;
> - if (ext4_test_bit(i, bitmap_bh->b_data))
> - break;
> - }
> + /*
> + * If the inode bitmap isn't in cache then the
> + * optimisation may end up performing two reads instead
> + * of one, so skip it.
> + */
> + if (!buffer_uptodate(bitmap_bh)) {
> brelse(bitmap_bh);
> - if (i == start + inodes_per_block) {
> - /* all other inodes are free, so skip I/O */
> - memset(bh->b_data, 0, bh->b_size);
> - set_buffer_uptodate(bh);
> - unlock_buffer(bh);
> - goto has_buffer;
> - }
> + goto make_io;
> + }
> + for (i = start; i < start + inodes_per_block; i++) {
> + if (i == inode_offset)
> + continue;
> + if (ext4_test_bit(i, bitmap_bh->b_data))
> + break;
> }
> + brelse(bitmap_bh);
> + if (i == start + inodes_per_block) {
> + /* all other inodes are free, so skip I/O */
> + memset(bh->b_data, 0, bh->b_size);
> + set_buffer_uptodate(bh);
> + unlock_buffer(bh);
> + goto has_buffer;
> + }
> + }
>
> make_io:
> - /*
> - * If we need to do any I/O, try to pre-readahead extra
> - * blocks from the inode table.
> - */
> - blk_start_plug(&plug);
> - if (EXT4_SB(sb)->s_inode_readahead_blks) {
> - ext4_fsblk_t b, end, table;
> - unsigned num;
> - __u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
> -
> - table = ext4_inode_table(sb, gdp);
> - /* s_inode_readahead_blks is always a power of 2 */
> - b = block & ~((ext4_fsblk_t) ra_blks - 1);
> - if (table > b)
> - b = table;
> - end = b + ra_blks;
> - num = EXT4_INODES_PER_GROUP(sb);
> - if (ext4_has_group_desc_csum(sb))
> - num -= ext4_itable_unused_count(sb, gdp);
> - table += num / inodes_per_block;
> - if (end > table)
> - end = table;
> - while (b <= end)
> - ext4_sb_breadahead_unmovable(sb, b++);
> - }
> + /*
> + * If we need to do any I/O, try to pre-readahead extra
> + * blocks from the inode table.
> + */
> + blk_start_plug(&plug);
> + if (EXT4_SB(sb)->s_inode_readahead_blks) {
> + ext4_fsblk_t b, end, table;
> + unsigned num;
> + __u32 ra_blks = EXT4_SB(sb)->s_inode_readahead_blks;
> +
> + table = ext4_inode_table(sb, gdp);
> + /* s_inode_readahead_blks is always a power of 2 */
> + b = block & ~((ext4_fsblk_t) ra_blks - 1);
> + if (table > b)
> + b = table;
> + end = b + ra_blks;
> + num = EXT4_INODES_PER_GROUP(sb);
> + if (ext4_has_group_desc_csum(sb))
> + num -= ext4_itable_unused_count(sb, gdp);
> + table += num / inodes_per_block;
> + if (end > table)
> + end = table;
> + while (b <= end)
> + ext4_sb_breadahead_unmovable(sb, b++);
> + }
>
> - /*
> - * There are other valid inodes in the buffer, this inode
> - * has in-inode xattrs, or we don't have this inode in memory.
> - * Read the block from disk.
> - */
> - trace_ext4_load_inode(sb, ino);
> - ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
> - blk_finish_plug(&plug);
> - wait_on_buffer(bh);
> - ext4_simulate_fail_bh(sb, bh, EXT4_SIM_INODE_EIO);
> - if (!buffer_uptodate(bh)) {
> - if (ret_block)
> - *ret_block = block;
> - brelse(bh);
> - return -EIO;
> - }
> + /*
> + * There are other valid inodes in the buffer, this inode
> + * has in-inode xattrs, or we don't have this inode in memory.
> + * Read the block from disk.
> + */
> + trace_ext4_load_inode(sb, ino);
> + ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO, NULL);
> + blk_finish_plug(&plug);
> + wait_on_buffer(bh);
> + ext4_simulate_fail_bh(sb, bh, EXT4_SIM_INODE_EIO);
> + if (!buffer_uptodate(bh)) {
> + if (ret_block)
> + *ret_block = block;
> + brelse(bh);
> + return -EIO;
> }
> has_buffer:
> iloc->bh = bh;
> --
> 2.31.1
>
--
Jan Kara <[email protected]>
SUSE Labs, CR