linux.git/fs/squashfs/file.c, branch for-next

Squashfs: Ensure all readahead pages have been used

2024-08-23T11:11:36+00:00

In the recent work to remove page->index, a sanity check
that ensured all the readhead pages were covered by the
Squashfs data block was removed [1].

To avoid any regression, this commit adds the sanity check
back in an equivalent way.  Namely the page actor will now
return error if any pages are unused after completion.

[1] https://lore.kernel.org/all/20240818235847.170468-3-phillip@squashfs.org.uk/

--

Signed-off-by: Phillip Lougher 
Link: https://lore.kernel.org/r/20240822233106.121522-1-phillip@squashfs.org.uk
V3: last_page should be actor->last_page
Signed-off-by: Christian Brauner

Squashfs: Rewrite and update squashfs_readahead_fragment() to not use page->index

2024-08-19T12:08:21+00:00

The previous implementation lacked error checking (e.g. the bytes
returned by squashfs_fill_page() is not checked), and the use of
page->index could not be removed without substantially rewriting
the routine to use the page actor abstraction used elsewhere.

Signed-off-by: Phillip Lougher 
Link: https://lore.kernel.org/r/20240818235847.170468-5-phillip@squashfs.org.uk
Signed-off-by: Christian Brauner

Squashfs: Update squashfs_readahead() to not use page->index

2024-08-19T12:08:20+00:00

This commit removes references to page->index in the pages returned
from __readahead_batch(), and instead uses the 'start' variable.

This does reveal a bug in the previous code in that 'start' was
not updated every time around the loop.  This is fixed in this
commit.

Signed-off-by: Phillip Lougher 
Link: https://lore.kernel.org/r/20240818235847.170468-3-phillip@squashfs.org.uk
Signed-off-by: Christian Brauner

Squashfs: Update page_actor to not use page->index

2024-08-19T12:08:20+00:00

This commit removes an unnecessary use of page->index,
and moves the other use over to folio->index.

Signed-off-by: Phillip Lougher 
Link: https://lore.kernel.org/r/20240818235847.170468-2-phillip@squashfs.org.uk
Signed-off-by: Christian Brauner

squashfs: remove calls to set the folio error flag

2024-05-08T15:41:28+00:00

Nobody checks the error flag on squashfs folios, so stop setting it.

Link: https://lkml.kernel.org/r/20240420025029.2166544-24-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Tested-by: Phillip Lougher 
Reviewed-by: Phillip Lougher 
Signed-off-by: Andrew Morton

Squashfs: fix variable overflow triggered by sysbot

2023-12-11T01:21:26+00:00

Sysbot reports a slab out of bounds write in squashfs_readahead().

This is ultimately caused by a file reporting an (infeasibly) large file
size (1407374883553280 bytes) with the minimum block size of 4K.

This causes variable overflow.

Link: https://lkml.kernel.org/r/20231113160901.6444-1-phillip@squashfs.org.uk
Signed-off-by: Phillip Lougher 
Reported-by: syzbot+604424eb051c2f696163@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000b1fda20609ede0d1@google.com/
Signed-off-by: Andrew Morton

squashfs: fix buffer release race condition in readahead code

2022-10-28T20:37:21+00:00

Fix a buffer release race condition, where the error value was used after
release.

Link: https://lkml.kernel.org/r/20221020223616.7571-4-phillip@squashfs.org.uk
Fixes: b09a7a036d20 ("squashfs: support reading fragments in readahead call")
Signed-off-by: Phillip Lougher 
Tested-by: Bagas Sanjaya 
Reported-by: Marc Miltenberger 
Cc: Dimitri John Ledkov 
Cc: Hsin-Yi Wang 
Cc: Mirsad Goran Todorovac 
Cc: Slade Watkins 
Cc: Thorsten Leemhuis 
Cc: 
Signed-off-by: Andrew Morton

squashfs: fix extending readahead beyond end of file

2022-10-28T20:37:21+00:00

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@squashfs.org.uk
Fixes: 8fc78b6fe24c ("squashfs: implement readahead")
Signed-off-by: Phillip Lougher 
Tested-by: Bagas Sanjaya 
Reported-by: Marc Miltenberger 
Cc: Dimitri John Ledkov 
Cc: Hsin-Yi Wang 
Cc: Mirsad Goran Todorovac 
Cc: Slade Watkins 
Cc: Thorsten Leemhuis 
Cc: 

Signed-off-by: Andrew Morton

squashfs: fix read regression introduced in readahead code

2022-10-28T20:37:21+00:00

Patch series "squashfs: fix some regressions introduced in the readahead
code".

This patchset fixes 3 regressions introduced by the recent readahead code
changes.  The first regression is causing "snaps" to randomly fail after a
couple of hours or days, which how the regression came to light.


This patch (of 3):

If a file isn't a whole multiple of the page size, the last page will have
trailing bytes unfilled.

There was a mistake in the readahead code which did this.  In particular
it incorrectly assumed that the last page in the readahead page array
(page[nr_pages - 1]) will always contain the last page in the block, which
if we're at file end, will be the page that needs to be zero filled.

But the readahead code may not return the last page in the block, which
means it is unmapped and will be skipped by the decompressors (a temporary
buffer used).

In this case the zero filling code will zero out the wrong page, leading
to data corruption.

Fix this by by extending the "page actor" to return the last page if
present, or NULL if a temporary buffer was used.

Link: https://lkml.kernel.org/r/20221020223616.7571-1-phillip@squashfs.org.uk
Link: https://lkml.kernel.org/r/20221020223616.7571-2-phillip@squashfs.org.uk
Fixes: 8fc78b6fe24c ("squashfs: implement readahead")
Link: https://lore.kernel.org/lkml/b0c258c3-6dcf-aade-efc4-d62a8b3a1ce2@alu.unizg.hr/
Signed-off-by: Phillip Lougher 
Reported-by: Mirsad Goran Todorovac 
Tested-by: Mirsad Goran Todorovac 
Tested-by: Slade Watkins 
Tested-by: Bagas Sanjaya 
Reported-by: Marc Miltenberger 
Cc: Dimitri John Ledkov 
Cc: Hsin-Yi Wang 
Cc: Thorsten Leemhuis 
Cc: 
Signed-off-by: Andrew Morton

squashfs: don't call kmalloc in decompressors

2022-08-28T21:02:45+00:00

The decompressors may be called while in an atomic section.  So move the
kmalloc() out of this path, and into the "page actor" init function.

This fixes a regression introduced by commit
f268eedddf35 ("squashfs: extend "page actor" to handle missing pages")

Link: https://lkml.kernel.org/r/20220822215430.15933-1-phillip@squashfs.org.uk
Fixes: f268eedddf35 ("squashfs: extend "page actor" to handle missing pages")
Reported-by: Chris Murphy 
Signed-off-by: Phillip Lougher 
Cc: 
Signed-off-by: Andrew Morton