This is a note to let you know that I've just added the patch titled
squashfs: fix extending readahead beyond end of file
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
squashfs-fix-extending-readahead-beyond-end-of-file.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c9199de82bad03bceb94ec3c5195c879d7e11911 Mon Sep 17 00:00:00 2001
From: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
Date: Thu, 20 Oct 2022 23:36:15 +0100
Subject: squashfs: fix extending readahead beyond end of file
From: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
commit c9199de82bad03bceb94ec3c5195c879d7e11911 upstream.
The readahead code will try to extend readahead to the entire size of the
Squashfs data block.
But, it didn't take into account that the last block at the end of the
file may not be a whole block. In this case, the code would extend
readahead to beyond the end of the file, leaving trailing pages.
Fix this by only requesting the expected number of pages.
Link: https://lkml.kernel.org/r/20221020223616.7571-3-phillip@xxxxxxxxxxxxxxx
Fixes: 8fc78b6fe24c ("squashfs: implement readahead")
Signed-off-by: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
Tested-by: Bagas Sanjaya <bagasdotme@xxxxxxxxx>
Reported-by: Marc Miltenberger <marcmiltenberger@xxxxxxxxx>
Cc: Dimitri John Ledkov <dimitri.ledkov@xxxxxxxxxxxxx>
Cc: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
Cc: Mirsad Goran Todorovac <mirsad.todorovac@xxxxxxxxxxxx>
Cc: Slade Watkins <srw@xxxxxxxxxxxxxxxx>
Cc: Thorsten Leemhuis <regressions@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/squashfs/file.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/fs/squashfs/file.c b/fs/squashfs/file.c
index e526eb7a1658..f0afd4d6fd30 100644
--- a/fs/squashfs/file.c
+++ b/fs/squashfs/file.c
@@ -559,6 +559,12 @@ static void squashfs_readahead(struct readahead_control *ractl)
unsigned int expected;
struct page *last_page;
+ expected = start >> msblk->block_log == file_end ?
+ (i_size_read(inode) & (msblk->block_size - 1)) :
+ msblk->block_size;
+
+ max_pages = (expected + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
nr_pages = __readahead_batch(ractl, pages, max_pages);
if (!nr_pages)
break;
@@ -567,13 +573,10 @@ static void squashfs_readahead(struct readahead_control *ractl)
goto skip_pages;
index = pages[0]->index >> shift;
+
if ((pages[nr_pages - 1]->index >> shift) != index)
goto skip_pages;
- expected = index == file_end ?
- (i_size_read(inode) & (msblk->block_size - 1)) :
- msblk->block_size;
-
if (index == file_end && squashfs_i(inode)->fragment_block !=
SQUASHFS_INVALID_BLK) {
res = squashfs_readahead_fragment(pages, nr_pages,
--
2.38.1
Patches currently in stable-queue which might be from phillip@xxxxxxxxxxxxxxx are
queue-6.0/squashfs-fix-extending-readahead-beyond-end-of-file.patch
queue-6.0/squashfs-fix-read-regression-introduced-in-readahead-code.patch
queue-6.0/squashfs-fix-buffer-release-race-condition-in-readahead-code.patch
