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BACKPORT: FROMGIT: f2fs: fix to avoid panic once fallocation fails for pinfile

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syzbot reports a f2fs bug as below:

------------[ cut here ]------------
kernel BUG at fs/f2fs/segment.c:2746!
CPU: 0 UID: 0 PID: 5323 Comm: syz.0.0 Not tainted 6.13.0-rc2-syzkaller-00018-g7cb1b4663150 #0
RIP: 0010:get_new_segment fs/f2fs/segment.c:2746 [inline]
RIP: 0010:new_curseg+0x1f52/0x1f70 fs/f2fs/segment.c:2876
Call Trace:
 <TASK>
 __allocate_new_segment+0x1ce/0x940 fs/f2fs/segment.c:3210
 f2fs_allocate_new_section fs/f2fs/segment.c:3224 [inline]
 f2fs_allocate_pinning_section+0xfa/0x4e0 fs/f2fs/segment.c:3238
 f2fs_expand_inode_data+0x696/0xca0 fs/f2fs/file.c:1830
 f2fs_fallocate+0x537/0xa10 fs/f2fs/file.c:1940
 vfs_fallocate+0x569/0x6e0 fs/open.c:327
 do_vfs_ioctl+0x258c/0x2e40 fs/ioctl.c:885
 __do_sys_ioctl fs/ioctl.c:904 [inline]
 __se_sys_ioctl+0x80/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Concurrent pinfile allocation may run out of free section, result in
panic in get_new_segment(), let's expand pin_sem lock coverage to
include f2fs_gc(), so that we can make sure to reclaim enough free
space for following allocation.

In addition, do below changes to enhance error path handling:
- call f2fs_bug_on() only in non-pinfile allocation path in
get_new_segment().
- call reset_curseg_fields() to reset all fields of curseg in
new_curseg()

Fixes: f5a53edcf0 ("f2fs: support aligned pinned file")
Reported-by: syzbot+15669ec8c35ddf6c3d43@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-f2fs-devel/675cd64e.050a0220.37aaf.00bb.GAE@google.com
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Bug: 399583169
(cherry picked from commit 48ea8b200414ac69ea96f4c231f5c7ef1fbeffef
 https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git dev)
Link: https://lore.kernel.org/linux-f2fs-devel/20250211063657.405289-1-chao@kernel.org/
[Jaegeuk: apply the pin_sem control only.]

Change-Id: Ie98beaed369e87f1fd14d10fb0e94b706f0bdd23
This commit is contained in:
Chao Yu
2025-02-11 14:36:57 +08:00
committed by Isaac Manjarres
parent 27895588a2
commit 64560e780e
1 changed files with 5 additions and 3 deletions
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8
fs/f2fs/file.c
View File

@@ -1808,16 +1808,18 @@ static int f2fs_expand_inode_data(struct inode *inode, loff_t offset,
map.m_len = sec_blks;
next_alloc:
f2fs_down_write(&sbi->pin_sem);
if (has_not_enough_free_secs(sbi, 0,
GET_SEC_FROM_SEG(sbi, overprovision_segments(sbi)))) {
f2fs_down_write(&sbi->gc_lock);
err = f2fs_gc(sbi, &gc_control);
if (err && err != -ENODATA)
if (err && err != -ENODATA) {
f2fs_up_write(&sbi->pin_sem);
goto out_err;
}
}
f2fs_down_write(&sbi->pin_sem);
f2fs_lock_op(sbi);
f2fs_allocate_new_section(sbi, CURSEG_COLD_DATA_PINNED, false);
f2fs_unlock_op(sbi);