linux.git/fs/nilfs2/btnode.c, branch v6.12

nilfs2: fix null-ptr-deref in block_dirty_buffer tracepoint

2024-11-12T01:20:23+00:00

When using the "block:block_dirty_buffer" tracepoint, mark_buffer_dirty()
may cause a NULL pointer dereference, or a general protection fault when
KASAN is enabled.

This happens because, since the tracepoint was added in
mark_buffer_dirty(), it references the dev_t member bh->b_bdev->bd_dev
regardless of whether the buffer head has a pointer to a block_device
structure.

In the current implementation, nilfs_grab_buffer(), which grabs a buffer
to read (or create) a block of metadata, including b-tree node blocks,
does not set the block device, but instead does so only if the buffer is
not in the "uptodate" state for each of its caller block reading
functions.  However, if the uptodate flag is set on a folio/page, and the
buffer heads are detached from it by try_to_free_buffers(), and new buffer
heads are then attached by create_empty_buffers(), the uptodate flag may
be restored to each buffer without the block device being set to
bh->b_bdev, and mark_buffer_dirty() may be called later in that state,
resulting in the bug mentioned above.

Fix this issue by making nilfs_grab_buffer() always set the block device
of the super block structure to the buffer head, regardless of the state
of the buffer's uptodate flag.

Link: https://lkml.kernel.org/r/20241106160811.3316-3-konishi.ryusuke@gmail.com
Fixes: 5305cb830834 ("block: add block_{touch|dirty}_buffer tracepoint")
Signed-off-by: Ryusuke Konishi 
Cc: Tejun Heo 
Cc: Ubisectech Sirius 
Cc: 
Signed-off-by: Andrew Morton

nilfs2: improve kernel-doc comments for b-tree node helpers

2024-09-02T03:43:36+00:00

Revise kernel-doc comments for helper functions related to changing the
search key for b-tree node blocks, and eliminate the following warnings
output by the kernel-doc script:

 fs/nilfs2/btnode.c:175: warning: Function parameter or struct member 'btnc'
  not described in 'nilfs_btnode_prepare_change_key'
 fs/nilfs2/btnode.c:175: warning: Function parameter or struct member 'ctxt'
  not described in 'nilfs_btnode_prepare_change_key'
 fs/nilfs2/btnode.c:238: warning: Function parameter or struct member 'btnc'
  not described in 'nilfs_btnode_commit_change_key'
 fs/nilfs2/btnode.c:238: warning: Function parameter or struct member 'ctxt'
  not described in 'nilfs_btnode_commit_change_key'
 fs/nilfs2/btnode.c:278: warning: Function parameter or struct member 'btnc'
  not described in 'nilfs_btnode_abort_change_key'
 fs/nilfs2/btnode.c:278: warning: Function parameter or struct member 'ctxt'
  not described in 'nilfs_btnode_abort_change_key'

Link: https://lkml.kernel.org/r/20240816074319.3253-4-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton

nilfs2: handle inconsistent state in nilfs_btnode_create_block()

2024-07-26T21:33:10+00:00

Syzbot reported that a buffer state inconsistency was detected in
nilfs_btnode_create_block(), triggering a kernel bug.

It is not appropriate to treat this inconsistency as a bug; it can occur
if the argument block address (the buffer index of the newly created
block) is a virtual block number and has been reallocated due to
corruption of the bitmap used to manage its allocation state.

So, modify nilfs_btnode_create_block() and its callers to treat it as a
possible filesystem error, rather than triggering a kernel bug.

Link: https://lkml.kernel.org/r/20240725052007.4562-1-konishi.ryusuke@gmail.com
Fixes: a60be987d45d ("nilfs2: B-tree node cache")
Signed-off-by: Ryusuke Konishi 
Reported-by: syzbot+89cc4f2324ed37988b60@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=89cc4f2324ed37988b60
Cc: 
Signed-off-by: Andrew Morton

nilfs2: convert nilfs_page_bug() to nilfs_folio_bug()

2023-12-11T01:21:48+00:00

All callers have a folio now, so convert it.

Link: https://lkml.kernel.org/r/20231127143036.2425-18-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton

nilfs2: convert nilfs_btnode_abort_change_key to use a folio

2023-12-11T01:21:30+00:00

Saves one call to compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-21-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton

nilfs2: convert nilfs_btnode_commit_change_key to use a folio

2023-12-11T01:21:30+00:00

Saves one call to compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-20-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton

nilfs2: convert nilfs_btnode_prepare_change_key to use a folio

2023-12-11T01:21:30+00:00

Saves three calls to compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-19-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton

nilfs2: convert nilfs_btnode_delete to use a folio

2023-12-11T01:21:30+00:00

Saves six calls to compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-18-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton

nilfs2: convert nilfs_btnode_submit_block to use a folio

2023-12-11T01:21:29+00:00

Saves two calls to compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-17-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton

nilfs2: convert nilfs_btnode_create_block to use a folio

2023-12-11T01:21:29+00:00

Saves two calls to compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-16-konishi.ryusuke@gmail.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Ryusuke Konishi 
Signed-off-by: Andrew Morton