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-rw-r--r--fs/ext4/extents.c135
1 files changed, 89 insertions, 46 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 2352467..8926623 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3153,29 +3153,28 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
struct ext4_extent_header *eh;
struct ext4_map_blocks split_map;
struct ext4_extent zero_ex;
- struct ext4_extent *ex;
+ struct ext4_extent *ex, *abut_ex;
ext4_lblk_t ee_block, eof_block;
- unsigned int ee_len, depth;
- int allocated, max_zeroout = 0;
+ unsigned int ee_len, depth, map_len = map->m_len;
+ int allocated = 0, max_zeroout = 0;
int err = 0;
int split_flag = 0;
ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
"block %llu, max_blocks %u\n", inode->i_ino,
- (unsigned long long)map->m_lblk, map->m_len);
+ (unsigned long long)map->m_lblk, map_len);
sbi = EXT4_SB(inode->i_sb);
eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
inode->i_sb->s_blocksize_bits;
- if (eof_block < map->m_lblk + map->m_len)
- eof_block = map->m_lblk + map->m_len;
+ if (eof_block < map->m_lblk + map_len)
+ eof_block = map->m_lblk + map_len;
depth = ext_depth(inode);
eh = path[depth].p_hdr;
ex = path[depth].p_ext;
ee_block = le32_to_cpu(ex->ee_block);
ee_len = ext4_ext_get_actual_len(ex);
- allocated = ee_len - (map->m_lblk - ee_block);
zero_ex.ee_len = 0;
trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
@@ -3186,77 +3185,121 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
/*
* Attempt to transfer newly initialized blocks from the currently
- * uninitialized extent to its left neighbor. This is much cheaper
+ * uninitialized extent to its neighbor. This is much cheaper
* than an insertion followed by a merge as those involve costly
- * memmove() calls. This is the common case in steady state for
- * workloads doing fallocate(FALLOC_FL_KEEP_SIZE) followed by append
- * writes.
+ * memmove() calls. Transferring to the left is the common case in
+ * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
+ * followed by append writes.
*
* Limitations of the current logic:
- * - L1: we only deal with writes at the start of the extent.
- * The approach could be extended to writes at the end
- * of the extent but this scenario was deemed less common.
- * - L2: we do not deal with writes covering the whole extent.
+ * - L1: we do not deal with writes covering the whole extent.
* This would require removing the extent if the transfer
* is possible.
- * - L3: we only attempt to merge with an extent stored in the
+ * - L2: we only attempt to merge with an extent stored in the
* same extent tree node.
*/
- if ((map->m_lblk == ee_block) && /*L1*/
- (map->m_len < ee_len) && /*L2*/
- (ex > EXT_FIRST_EXTENT(eh))) { /*L3*/
- struct ext4_extent *prev_ex;
+ if ((map->m_lblk == ee_block) &&
+ /* See if we can merge left */
+ (map_len < ee_len) && /*L1*/
+ (ex > EXT_FIRST_EXTENT(eh))) { /*L2*/
ext4_lblk_t prev_lblk;
ext4_fsblk_t prev_pblk, ee_pblk;
- unsigned int prev_len, write_len;
+ unsigned int prev_len;
- prev_ex = ex - 1;
- prev_lblk = le32_to_cpu(prev_ex->ee_block);
- prev_len = ext4_ext_get_actual_len(prev_ex);
- prev_pblk = ext4_ext_pblock(prev_ex);
+ abut_ex = ex - 1;
+ prev_lblk = le32_to_cpu(abut_ex->ee_block);
+ prev_len = ext4_ext_get_actual_len(abut_ex);
+ prev_pblk = ext4_ext_pblock(abut_ex);
ee_pblk = ext4_ext_pblock(ex);
- write_len = map->m_len;
/*
- * A transfer of blocks from 'ex' to 'prev_ex' is allowed
+ * A transfer of blocks from 'ex' to 'abut_ex' is allowed
* upon those conditions:
- * - C1: prev_ex is initialized,
- * - C2: prev_ex is logically abutting ex,
- * - C3: prev_ex is physically abutting ex,
- * - C4: prev_ex can receive the additional blocks without
+ * - C1: abut_ex is initialized,
+ * - C2: abut_ex is logically abutting ex,
+ * - C3: abut_ex is physically abutting ex,
+ * - C4: abut_ex can receive the additional blocks without
* overflowing the (initialized) length limit.
*/
- if ((!ext4_ext_is_uninitialized(prev_ex)) && /*C1*/
+ if ((!ext4_ext_is_uninitialized(abut_ex)) && /*C1*/
((prev_lblk + prev_len) == ee_block) && /*C2*/
((prev_pblk + prev_len) == ee_pblk) && /*C3*/
- (prev_len < (EXT_INIT_MAX_LEN - write_len))) { /*C4*/
+ (prev_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/
err = ext4_ext_get_access(handle, inode, path + depth);
if (err)
goto out;
trace_ext4_ext_convert_to_initialized_fastpath(inode,
- map, ex, prev_ex);
+ map, ex, abut_ex);
- /* Shift the start of ex by 'write_len' blocks */
- ex->ee_block = cpu_to_le32(ee_block + write_len);
- ext4_ext_store_pblock(ex, ee_pblk + write_len);
- ex->ee_len = cpu_to_le16(ee_len - write_len);
+ /* Shift the start of ex by 'map_len' blocks */
+ ex->ee_block = cpu_to_le32(ee_block + map_len);
+ ext4_ext_store_pblock(ex, ee_pblk + map_len);
+ ex->ee_len = cpu_to_le16(ee_len - map_len);
ext4_ext_mark_uninitialized(ex); /* Restore the flag */
- /* Extend prev_ex by 'write_len' blocks */
- prev_ex->ee_len = cpu_to_le16(prev_len + write_len);
+ /* Extend abut_ex by 'map_len' blocks */
+ abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
- /* Mark the block containing both extents as dirty */
- ext4_ext_dirty(handle, inode, path + depth);
+ /* Result: number of initialized blocks past m_lblk */
+ allocated = map_len;
+ }
+ } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
+ (map_len < ee_len) && /*L1*/
+ ex < EXT_LAST_EXTENT(eh)) { /*L2*/
+ /* See if we can merge right */
+ ext4_lblk_t next_lblk;
+ ext4_fsblk_t next_pblk, ee_pblk;
+ unsigned int next_len;
+
+ abut_ex = ex + 1;
+ next_lblk = le32_to_cpu(abut_ex->ee_block);
+ next_len = ext4_ext_get_actual_len(abut_ex);
+ next_pblk = ext4_ext_pblock(abut_ex);
+ ee_pblk = ext4_ext_pblock(ex);
- /* Update path to point to the right extent */
- path[depth].p_ext = prev_ex;
+ /*
+ * A transfer of blocks from 'ex' to 'abut_ex' is allowed
+ * upon those conditions:
+ * - C1: abut_ex is initialized,
+ * - C2: abut_ex is logically abutting ex,
+ * - C3: abut_ex is physically abutting ex,
+ * - C4: abut_ex can receive the additional blocks without
+ * overflowing the (initialized) length limit.
+ */
+ if ((!ext4_ext_is_uninitialized(abut_ex)) && /*C1*/
+ ((map->m_lblk + map_len) == next_lblk) && /*C2*/
+ ((ee_pblk + ee_len) == next_pblk) && /*C3*/
+ (next_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/
+ err = ext4_ext_get_access(handle, inode, path + depth);
+ if (err)
+ goto out;
+
+ trace_ext4_ext_convert_to_initialized_fastpath(inode,
+ map, ex, abut_ex);
+
+ /* Shift the start of abut_ex by 'map_len' blocks */
+ abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
+ ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
+ ex->ee_len = cpu_to_le16(ee_len - map_len);
+ ext4_ext_mark_uninitialized(ex); /* Restore the flag */
+
+ /* Extend abut_ex by 'map_len' blocks */
+ abut_ex->ee_len = cpu_to_le16(next_len + map_len);
/* Result: number of initialized blocks past m_lblk */
- allocated = write_len;
- goto out;
+ allocated = map_len;
}
}
+ if (allocated) {
+ /* Mark the block containing both extents as dirty */
+ ext4_ext_dirty(handle, inode, path + depth);
+
+ /* Update path to point to the right extent */
+ path[depth].p_ext = abut_ex;
+ goto out;
+ } else
+ allocated = ee_len - (map->m_lblk - ee_block);
WARN_ON(map->m_lblk < ee_block);
/*
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