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ext4: remove an unnecessary if statement in __ext4_get_inode_loc()

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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 <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210826130412.3921207-3-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Zhang Yi 2021-08-26 21:04:08 +08:00 committed by Theodore Ts'o
parent 0904c9ae34
commit 8e33fadf94
1 changed files with 79 additions and 85 deletions
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164
fs/ext4/inode.c
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@ -4337,99 +4337,93 @@ 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))
goto has_buffer;
if (ext4_buffer_uptodate(bh)) {
/* someone brought it uptodate while we waited */
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);
/* 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;
}
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;
}
/*
* 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);
/* 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;
}
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;
/*
* 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++);
}
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;