[PATCH 0/4] ext4 fixes

[PATCH 0/4] ext4 fixes

[Sascha Hauer]

This series fixes some issues with the ext4 code regarding to sparse
files.

Sascha

Sascha Hauer (4):
  fs: ext4: Fix out of bounds memset
  fs: ext4: remove unnecessarily clever file read
  fs: ext4: Fix handling of sparse files
  fs: ext4: return NULL instead of 0

 fs/ext4/ext4_common.c | 32 +++++++++++------------
 fs/ext4/ext4fs.c      | 61 +++++--------------------------------------
 2 files changed, 23 insertions(+), 70 deletions(-)

-- 
2.24.0.rc1


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[PATCH 1/4] fs: ext4: Fix out of bounds memset

[Sascha Hauer]

When a block we read is a sparse block, we memset the corresponding
output buffer to zero. If that block is the last block we read, we
may not memset the whole block, but only up to the length of the output
buffer, which may be shorter than a full block.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 fs/ext4/ext4fs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index bfc5f27cc3..acecccd6b9 100644
--- a/fs/ext4/ext4fs.c
+++ b/fs/ext4/ext4fs.c
@@ -135,7 +135,7 @@ int ext4fs_read_file(struct ext2fs_node *node, int pos,
 					return ret;
 				previous_block_number = -1;
 			}
-			memset(buf, 0, blocksize - skipfirst);
+			memset(buf, 0, blockend);
 		}
 		buf += blocksize - skipfirst;
 	}
-- 
2.24.0.rc1


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[PATCH 2/4] fs: ext4: remove unnecessarily clever file read

[Sascha Hauer]

ext4fs_read_file() tries to tries to bundle contiguous block reads into
longer reads from the device. In barebox we cache in the block layer
already, so this is unnecessary. Simplify the code by removing the
bundled reads.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 fs/ext4/ext4fs.c | 59 +++++-------------------------------------------
 1 file changed, 6 insertions(+), 53 deletions(-)

diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index acecccd6b9..2d231d273a 100644
--- a/fs/ext4/ext4fs.c
+++ b/fs/ext4/ext4fs.c
@@ -55,12 +55,6 @@ int ext4fs_read_file(struct ext2fs_node *node, int pos,
 	int log2blocksize = LOG2_EXT2_BLOCK_SIZE(node->data);
 	int blocksize = 1 << (log2blocksize + DISK_SECTOR_BITS);
 	unsigned int filesize = le32_to_cpu(node->inode.size);
-	int previous_block_number = -1;
-	int delayed_start = 0;
-	int delayed_extent = 0;
-	int delayed_skipfirst = 0;
-	int delayed_next = 0;
-	char *delayed_buf = NULL;
 	short ret;
 	struct ext_filesystem *fs = node->data->fs;
 
@@ -75,6 +69,7 @@ int ext4fs_read_file(struct ext2fs_node *node, int pos,
 		int blockoff = pos % blocksize;
 		int blockend = blocksize;
 		int skipfirst = 0;
+
 		blknr = read_allocated_block(node, i);
 		if (blknr < 0)
 			return blknr;
@@ -95,59 +90,17 @@ int ext4fs_read_file(struct ext2fs_node *node, int pos,
 			skipfirst = blockoff;
 			blockend -= skipfirst;
 		}
+
 		if (blknr) {
-			if (previous_block_number != -1) {
-				if (delayed_next == blknr) {
-					delayed_extent += blockend;
-					delayed_next += blockend >> SECTOR_BITS;
-				} else {	/* spill */
-					ret = ext4fs_devread(fs, delayed_start,
-							delayed_skipfirst,
-							delayed_extent,
-							delayed_buf);
-					if (ret)
-						return ret;
-					previous_block_number = blknr;
-					delayed_start = blknr;
-					delayed_extent = blockend;
-					delayed_skipfirst = skipfirst;
-					delayed_buf = buf;
-					delayed_next = blknr +
-						(blockend >> SECTOR_BITS);
-				}
-			} else {
-				previous_block_number = blknr;
-				delayed_start = blknr;
-				delayed_extent = blockend;
-				delayed_skipfirst = skipfirst;
-				delayed_buf = buf;
-				delayed_next = blknr +
-					(blockend >> SECTOR_BITS);
-			}
+			ret = ext4fs_devread(fs, blknr, skipfirst, blockend, buf);
+			if (ret)
+				return ret;
 		} else {
-			if (previous_block_number != -1) {
-				/* spill */
-				ret = ext4fs_devread(fs, delayed_start,
-							delayed_skipfirst,
-							delayed_extent,
-							delayed_buf);
-				if (ret)
-					return ret;
-				previous_block_number = -1;
-			}
 			memset(buf, 0, blockend);
 		}
+
 		buf += blocksize - skipfirst;
 	}
-	if (previous_block_number != -1) {
-		/* spill */
-		ret = ext4fs_devread(fs, delayed_start,
-					delayed_skipfirst, delayed_extent,
-					delayed_buf);
-		if (ret)
-			return ret;
-		previous_block_number = -1;
-	}
 
 	return len;
 }
-- 
2.24.0.rc1


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[PATCH 3/4] fs: ext4: Fix handling of sparse files

[Sascha Hauer]

Adoption of U-Boot commit:

| commit f81db56f2fd6dc16efeaec2961121244765a1f11
| Author: Stefan Brüns <stefan.bruens@rwth-aachen.de>
| Date:   Sat Nov 5 22:17:14 2016 +0100
|
|     ext4: Fix handling of sparse files
|
|     A sparse file may have regions not mapped by any extents, at the start
|     or at the end of the file, or anywhere between, thus not finding a
|     matching extent region is never an error.
|
|     Found by python filesystem tests.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 fs/ext4/ext4_common.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index 55e837b4bd..2703b55e99 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -167,10 +167,11 @@ long int read_allocated_block(struct ext2fs_node *node, int fileblock)
 	log2_blksz = LOG2_EXT2_BLOCK_SIZE(node->data);
 
 	if (le32_to_cpu(inode->flags) & EXT4_EXTENTS_FL) {
+		long int startblock, endblock;
 		char *buf = zalloc(blksz);
 		struct ext4_extent_header *ext_block;
 		struct ext4_extent *extent;
-		int i = -1;
+		int i;
 
 		if (!buf)
 			return -ENOMEM;
@@ -186,28 +187,27 @@ long int read_allocated_block(struct ext2fs_node *node, int fileblock)
 
 		extent = (struct ext4_extent *)(ext_block + 1);
 
-		do {
-			i++;
-			if (i >= le16_to_cpu(ext_block->eh_entries))
-				break;
-		} while (fileblock >= le32_to_cpu(extent[i].ee_block));
+		for (i = 0; i < le16_to_cpu(ext_block->eh_entries); i++) {
+			startblock = le32_to_cpu(extent[i].ee_block);
+			endblock = startblock + le16_to_cpu(extent[i].ee_len);
 
-		if (--i >= 0) {
-			fileblock -= le32_to_cpu(extent[i].ee_block);
-			if (fileblock >= le16_to_cpu(extent[i].ee_len)) {
+			if (startblock > fileblock) {
+				/* Sparse file */
 				free(buf);
 				return 0;
 			}
 
-			start = le16_to_cpu(extent[i].ee_start_hi);
-			start = (start << 32) +
+			if (fileblock < endblock) {
+				start = le16_to_cpu(extent[i].ee_start_hi);
+				start = (start << 32) +
 					le32_to_cpu(extent[i].ee_start_lo);
-			free(buf);
-			return fileblock + start;
+				free(buf);
+				return (fileblock - startblock) + start;
+			}
 		}
 
 		free(buf);
-		return -EIO;
+		return 0;
 	}
 
 	if (fileblock < INDIRECT_BLOCKS) {
-- 
2.24.0.rc1


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[PATCH 4/4] fs: ext4: return NULL instead of 0

[Sascha Hauer]

ext4fs_get_extent_block() returns a pointer, so return NULL instead of
integer 0.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 fs/ext4/ext4_common.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index 2703b55e99..c9f27f1278 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -52,7 +52,7 @@ static struct ext4_extent_header *ext4fs_get_extent_block(struct ext2_data *data
 		index = (struct ext4_extent_idx *)(ext_block + 1);
 
 		if (le16_to_cpu(ext_block->eh_magic) != EXT4_EXT_MAGIC)
-			return 0;
+			return NULL;
 
 		if (ext_block->eh_depth == 0)
 			return ext_block;
@@ -64,7 +64,7 @@ static struct ext4_extent_header *ext4fs_get_extent_block(struct ext2_data *data
 		} while (fileblock >= le32_to_cpu(index[i].ei_block));
 
 		if (--i < 0)
-			return 0;
+			return NULL;
 
 		block = le16_to_cpu(index[i].ei_leaf_hi);
 		block = (block << 32) + le32_to_cpu(index[i].ei_leaf_lo);
-- 
2.24.0.rc1


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