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author | Liu Bo <bo.li.liu@oracle.com> | 2017-11-22 00:35:40 +0300 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2017-11-27 19:41:19 +0300 |
commit | ebb70442cdd4872260c2415929c456be3562da82 (patch) | |
tree | 06b3108c80b86f692d988102489882ab8bb4b711 /fs | |
parent | eae8d82529dd9820e206ecba0047b806c4410e65 (diff) | |
download | linux-ebb70442cdd4872260c2415929c456be3562da82.tar.xz |
Btrfs: fix list_add corruption and soft lockups in fsync
Xfstests btrfs/146 revealed this corruption,
[ 58.138831] Buffer I/O error on dev dm-0, logical block 2621424, async page read
[ 58.151233] BTRFS error (device sdf): bdev /dev/mapper/error-test errs: wr 1, rd 0, flush 0, corrupt 0, gen 0
[ 58.152403] list_add corruption. prev->next should be next (ffff88005e6775d8), but was ffffc9000189be88. (prev=ffffc9000189be88).
[ 58.153518] ------------[ cut here ]------------
[ 58.153892] WARNING: CPU: 1 PID: 1287 at lib/list_debug.c:31 __list_add_valid+0x169/0x1f0
...
[ 58.157379] RIP: 0010:__list_add_valid+0x169/0x1f0
...
[ 58.161956] Call Trace:
[ 58.162264] btrfs_log_inode_parent+0x5bd/0xfb0 [btrfs]
[ 58.163583] btrfs_log_dentry_safe+0x60/0x80 [btrfs]
[ 58.164003] btrfs_sync_file+0x4c2/0x6f0 [btrfs]
[ 58.164393] vfs_fsync_range+0x5f/0xd0
[ 58.164898] do_fsync+0x5a/0x90
[ 58.165170] SyS_fsync+0x10/0x20
[ 58.165395] entry_SYSCALL_64_fastpath+0x1f/0xbe
...
It turns out that we could record btrfs_log_ctx:io_err in
log_one_extents when IO fails, but make log_one_extents() return '0'
instead of -EIO, so the IO error is not acknowledged by the callers,
i.e. btrfs_log_inode_parent(), which would remove btrfs_log_ctx:list
from list head 'root->log_ctxs'. Since btrfs_log_ctx is allocated
from stack memory, it'd get freed with a object alive on the
list. then a future list_add will throw the above warning.
This returns the correct error in the above case.
Jeff also reported this while testing against his fsync error
patch set[1].
[1]: https://www.spinics.net/lists/linux-btrfs/msg65308.html
"btrfs list corruption and soft lockups while testing writeback error handling"
Fixes: 8407f553268a4611f254 ("Btrfs: fix data corruption after fast fsync and writeback error")
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/btrfs/file.c | 5 | ||||
-rw-r--r-- | fs/btrfs/tree-log.c | 2 |
2 files changed, 4 insertions, 3 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 2de7b4f4ca3c..eb1bac7c8553 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2057,6 +2057,8 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) len = (u64)end - (u64)start + 1; trace_btrfs_sync_file(file, datasync); + btrfs_init_log_ctx(&ctx, inode); + /* * We write the dirty pages in the range and wait until they complete * out of the ->i_mutex. If so, we can flush the dirty pages by @@ -2203,8 +2205,6 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) } trans->sync = true; - btrfs_init_log_ctx(&ctx, inode); - ret = btrfs_log_dentry_safe(trans, root, dentry, start, end, &ctx); if (ret < 0) { /* Fallthrough and commit/free transaction. */ @@ -2262,6 +2262,7 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) ret = btrfs_end_transaction(trans); } out: + ASSERT(list_empty(&ctx.list)); err = file_check_and_advance_wb_err(file); if (!ret) ret = err; diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index aa7c71cff575..7bf9b31561db 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -4102,7 +4102,7 @@ static int log_one_extent(struct btrfs_trans_handle *trans, if (ordered_io_err) { ctx->io_err = -EIO; - return 0; + return ctx->io_err; } btrfs_init_map_token(&token); |