From 8e33fadf945a918c50d92fab6a769661df484156 Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Thu, 26 Aug 2021 21:04:08 +0800 Subject: [PATCH] ext4: remove an unnecessary if statement in __ext4_get_inode_loc() 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 Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20210826130412.3921207-3-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o --- 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 532443f89015..c26f946cf04a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -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)) { - /* 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; -- 2.11.0