| Message ID | 20171121213540.20656-1-bo.li.liu@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Nov 21, 2017 at 02:35:40PM -0700, Liu Bo wrote: > 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> -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 504e96d..1e6956b 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2066,6 +2066,8 @@ 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 @@ -2212,8 +2214,6 @@ 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. */ @@ -2271,6 +2271,7 @@ 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 c800d06..d300284 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -4100,7 +4100,7 @@ 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);
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> --- v2: - Initialize ctx at the very beginning of fsync so that we can check if list is empty at out label fs/btrfs/file.c | 5 +++-- fs/btrfs/tree-log.c | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-)