From: Sascha Hauer <s.hauer@pengutronix.de>
To: Barebox List <barebox@lists.infradead.org>
Subject: [PATCH 3/4] fs: ext4: Fix handling of sparse files
Date: Tue, 29 Oct 2019 10:10:28 +0100 [thread overview]
Message-ID: <20191029091029.22215-4-s.hauer@pengutronix.de> (raw)
In-Reply-To: <20191029091029.22215-1-s.hauer@pengutronix.de>
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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next prev parent reply other threads:[~2019-10-29 9:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-29 9:10 [PATCH 0/4] ext4 fixes Sascha Hauer
2019-10-29 9:10 ` [PATCH 1/4] fs: ext4: Fix out of bounds memset Sascha Hauer
2019-10-29 9:10 ` [PATCH 2/4] fs: ext4: remove unnecessarily clever file read Sascha Hauer
2019-10-29 9:10 ` Sascha Hauer [this message]
2019-10-29 9:10 ` [PATCH 4/4] fs: ext4: return NULL instead of 0 Sascha Hauer
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