1 files changed, 51 insertions, 16 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 228eeaf2dccf..ee611daf0748 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2631,11 +2631,21 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
         struct ext4_extent *ex2 = NULL;
         struct ext4_extent *ex3 = NULL;
         struct ext4_extent_header *eh;
-        ext4_lblk_t ee_block;
+        ext4_lblk_t ee_block, eof_block;
         unsigned int allocated, ee_len, depth;
         ext4_fsblk_t newblock;
         int err = 0;
         int ret = 0;
+        int may_zeroout;
+
+        ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
+                "block %llu, max_blocks %u\n", inode->i_ino,
+                (unsigned long long)iblock, max_blocks);
+
+        eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
+                inode->i_sb->s_blocksize_bits;
+        if (eof_block < iblock + max_blocks)
+                eof_block = iblock + max_blocks;
 
         depth = ext_depth(inode);
         eh = path[depth].p_hdr;
@@ -2644,16 +2654,23 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
         ee_len = ext4_ext_get_actual_len(ex);
         allocated = ee_len - (iblock - ee_block);
         newblock = iblock - ee_block + ext_pblock(ex);
+
         ex2 = ex;
         orig_ex.ee_block = ex->ee_block;
         orig_ex.ee_len   = cpu_to_le16(ee_len);
         ext4_ext_store_pblock(&orig_ex, ext_pblock(ex));
 
+        /*
+         * It is safe to convert extent to initialized via explicit
+         * zeroout only if extent is fully insde i_size or new_size.
+         */
+        may_zeroout = ee_block + ee_len <= eof_block;
+
         err = ext4_ext_get_access(handle, inode, path + depth);
         if (err)
                 goto out;
         /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
-        if (ee_len <= 2*EXT4_EXT_ZERO_LEN) {
+        if (ee_len <= 2*EXT4_EXT_ZERO_LEN && may_zeroout) {
                 err =  ext4_ext_zeroout(inode, &orig_ex);
                 if (err)
                         goto fix_extent_len;
@@ -2684,7 +2701,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
         if (allocated > max_blocks) {
                 unsigned int newdepth;
                 /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */
-                if (allocated <= EXT4_EXT_ZERO_LEN) {
+                if (allocated <= EXT4_EXT_ZERO_LEN && may_zeroout) {
                         /*
                          * iblock == ee_block is handled by the zerouout
                          * at the beginning.
@@ -2760,7 +2777,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
                 ex3->ee_len = cpu_to_le16(allocated - max_blocks);
                 ext4_ext_mark_uninitialized(ex3);
                 err = ext4_ext_insert_extent(handle, inode, path, ex3, 0);
-                if (err == -ENOSPC) {
+                if (err == -ENOSPC && may_zeroout) {
                         err =  ext4_ext_zeroout(inode, &orig_ex);
                         if (err)
                                 goto fix_extent_len;
@@ -2784,8 +2801,10 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
                  * update the extent length after successful insert of the
                  * split extent
                  */
-                orig_ex.ee_len = cpu_to_le16(ee_len -
-                                                ext4_ext_get_actual_len(ex3));
+                ee_len -= ext4_ext_get_actual_len(ex3);
+                orig_ex.ee_len = cpu_to_le16(ee_len);
+                may_zeroout = ee_block + ee_len <= eof_block;
+
                 depth = newdepth;
                 ext4_ext_drop_refs(path);
                 path = ext4_ext_find_extent(inode, iblock, path);
@@ -2809,7 +2828,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
                  * otherwise give the extent a chance to merge to left
                  */
                 if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN &&
-                                                        iblock != ee_block) {
+                        iblock != ee_block && may_zeroout) {
                         err =  ext4_ext_zeroout(inode, &orig_ex);
                         if (err)
                                 goto fix_extent_len;
@@ -2878,7 +2897,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
         goto out;
 insert:
         err = ext4_ext_insert_extent(handle, inode, path, &newex, 0);
-        if (err == -ENOSPC) {
+        if (err == -ENOSPC && may_zeroout) {
                 err =  ext4_ext_zeroout(inode, &orig_ex);
                 if (err)
                         goto fix_extent_len;
@@ -2938,14 +2957,21 @@ static int ext4_split_unwritten_extents(handle_t *handle,
         struct ext4_extent *ex2 = NULL;
         struct ext4_extent *ex3 = NULL;
         struct ext4_extent_header *eh;
-        ext4_lblk_t ee_block;
+        ext4_lblk_t ee_block, eof_block;
         unsigned int allocated, ee_len, depth;
         ext4_fsblk_t newblock;
         int err = 0;
+        int may_zeroout;
+
+        ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
+                "block %llu, max_blocks %u\n", inode->i_ino,
+                (unsigned long long)iblock, max_blocks);
+
+        eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
+                inode->i_sb->s_blocksize_bits;
+        if (eof_block < iblock + max_blocks)
+                eof_block = iblock + max_blocks;
 
-        ext_debug("ext4_split_unwritten_extents: inode %lu,"
-                  "iblock %llu, max_blocks %u\n", inode->i_ino,
-                  (unsigned long long)iblock, max_blocks);
         depth = ext_depth(inode);
         eh = path[depth].p_hdr;
         ex = path[depth].p_ext;
@@ -2953,12 +2979,19 @@ static int ext4_split_unwritten_extents(handle_t *handle,
         ee_len = ext4_ext_get_actual_len(ex);
         allocated = ee_len - (iblock - ee_block);
         newblock = iblock - ee_block + ext_pblock(ex);
+
         ex2 = ex;
         orig_ex.ee_block = ex->ee_block;
         orig_ex.ee_len   = cpu_to_le16(ee_len);
         ext4_ext_store_pblock(&orig_ex, ext_pblock(ex));
 
         /*
+         * It is safe to convert extent to initialized via explicit
+         * zeroout only if extent is fully insde i_size or new_size.
+         */
+        may_zeroout = ee_block + ee_len <= eof_block;
+
+        /*
          * If the uninitialized extent begins at the same logical
          * block where the write begins, and the write completely
          * covers the extent, then we don't need to split it.
@@ -2992,7 +3025,7 @@ static int ext4_split_unwritten_extents(handle_t *handle,
                 ex3->ee_len = cpu_to_le16(allocated - max_blocks);
                 ext4_ext_mark_uninitialized(ex3);
                 err = ext4_ext_insert_extent(handle, inode, path, ex3, flags);
-                if (err == -ENOSPC) {
+                if (err == -ENOSPC && may_zeroout) {
                         err =  ext4_ext_zeroout(inode, &orig_ex);
                         if (err)
                                 goto fix_extent_len;
@@ -3016,8 +3049,10 @@ static int ext4_split_unwritten_extents(handle_t *handle,
                  * update the extent length after successful insert of the
                  * split extent
                  */
-                orig_ex.ee_len = cpu_to_le16(ee_len -
-                                                ext4_ext_get_actual_len(ex3));
+                ee_len -= ext4_ext_get_actual_len(ex3);
+                orig_ex.ee_len = cpu_to_le16(ee_len);
+                may_zeroout = ee_block + ee_len <= eof_block;
+
                 depth = newdepth;
                 ext4_ext_drop_refs(path);
                 path = ext4_ext_find_extent(inode, iblock, path);
@@ -3063,7 +3098,7 @@ static int ext4_split_unwritten_extents(handle_t *handle,
         goto out;
 insert:
         err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
-        if (err == -ENOSPC) {
+        if (err == -ENOSPC && may_zeroout) {
                 err =  ext4_ext_zeroout(inode, &orig_ex);
                 if (err)
                         goto fix_extent_len;