kernel.git/include/trace/events/ext4.h, branch linux-5.8.y

ext4: limit the length of per-inode prealloc list

2020-09-03T09:29:37Z

[ Upstream commit 27bc446e2def38db3244a6eb4bb1d6312936610a ] In the scenario of writing sparse files, the per-inode prealloc list may be very long, resulting in high overhead for ext4_mb_use_preallocated(). To circumvent this problem, we limit the maximum length of per-inode prealloc list to 512 and allow users to modify it. After patching, we observed that the sys ratio of cpu has dropped, and the system throughput has increased significantly. We created a process to write the sparse file, and the running time of the process on the fixed kernel was significantly reduced, as follows: Running time on unfixed kernel： [root@TENCENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat real 0m2.051s user 0m0.008s sys 0m2.026s Running time on fixed kernel： [root@TENCENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat real 0m0.471s user 0m0.004s sys 0m0.395s Signed-off-by: Chunguang Xu Link: https://lore.kernel.org/r/d7a98178-056b-6db5-6bce-4ead23f4a257@gmail.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: mballoc: use lock for checking free blocks while retrying

2020-06-04T03:16:53Z

Currently while doing block allocation grp->bb_free may be getting modified if discard is happening in parallel. For e.g. consider a case where there are lot of threads who have preallocated lot of blocks and there is a thread which is trying to discard all of this group's PA. Now it could happen that we see all of those group's bb_free is zero and fail the allocation while there is sufficient space if we free up all the PA. So this patch adds another flag "EXT4_MB_STRICT_CHECK" which will be set if we are unable to allocate any blocks in the first try (since we may not have considered blocks about to be discarded from PA lists). So during retry attempt to allocate blocks we will use ext4_lock_group() for checking if the group is good or not. Signed-off-by: Ritesh Harjani Link: https://lore.kernel.org/r/9cb740a117c958c36596f167b12af1beae9a68b7.1589955723.git.riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o

ext4: translate a few more map flags to strings in tracepoints

2020-06-04T03:16:49Z

As new ext4_map_blocks() flags have been added, not all have gotten flag bit to string translations to make tracepoint output more readable. Fix that, and go one step further by adding a translation for the EXT4_EX_NOCACHE flag as well. The EXT4_EX_FORCE_CACHE flag can never be set in a tracepoint in the current code, so there's no need to bother with a translation for it right now. Signed-off-by: Eric Whitney Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20200415203140.30349-3-enwlinux@gmail.com Signed-off-by: Theodore Ts'o

ext4: remove EXT4_GET_BLOCKS_KEEP_SIZE flag

2020-06-04T03:16:48Z

The eofblocks code was removed in the 5.7 release by "ext4: remove EOFBLOCKS_FL and associated code" (4337ecd1fe99). The ext4_map_blocks() flag used to trigger it can now be removed as well. Signed-off-by: Eric Whitney Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20200415203140.30349-2-enwlinux@gmail.com Signed-off-by: Theodore Ts'o

ext4: fix extent_status trace points

2020-01-25T07:03:03Z

Show pblock only if it has meaningful value. # before ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [1/4294967294) 576460752303423487 H ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [2/4294967293) 576460752303423487 HR # after ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [1/4294967294) 0 H ext4:ext4_es_lookup_extent_exit: dev 253,0 ino 12 found 1 [2/4294967293) 0 HR Signed-off-by: Dmitry Monakhov Link: https://lore.kernel.org/r/20191114200147.1073-2-dmonakhov@gmail.com Signed-off-by: Theodore Ts'o

ext4: fix symbolic enum printing in trace output

2020-01-25T07:03:02Z

Trace's macro __print_flags() produce raw event's decraration w/o knowing actual flags value cat /sys/kernel/debug/tracing/events/ext4/ext4_ext_map_blocks_exit/format .. __print_flags(REC->mflags, "", { (1 << BH_New), For that reason we have to explicitly define it via special macro TRACE_DEFINE_ENUM() Also add missed EXTENT_STATUS_REFERENCED flag. #Before patch ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 2 flags lblk 0 pblk 4177 len 1 mflags 0x20 ret 1 ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 12 flags CREATE lblk 0 pblk 34304 len 1 mflags 0x60 ret 1 #With patch ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 2 flags lblk 0 pblk 4177 len 1 mflags M ret 1 ext4:ext4_ext_map_blocks_exit: dev 253,0 ino 12 flags CREATE lblk 0 pblk 34816 len 1 mflags NM ret 1 Signed-off-by: Dmitry Monakhov Link: https://lore.kernel.org/r/20191114200147.1073-1-dmonakhov@gmail.com Signed-off-by: Theodore Ts'o

ext4: Reserve revoke credits for freed blocks

2019-11-05T21:00:49Z

So far we have reserved only relatively high fixed amount of revoke credits for each transaction. We over-reserved by large amount for most cases but when freeing large directories or files with data journalling, the fixed amount is not enough. In fact the worst case estimate is inconveniently large (maximum extent size) for freeing of one extent. We fix this by doing proper estimate of the amount of blocks that need to be revoked when removing blocks from the inode due to truncate or hole punching and otherwise reserve just a small amount of revoke credits for each transaction to accommodate freeing of xattrs block or so. Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20191105164437.32602-23-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: force inode writes when nfsd calls commit_metadata()

2018-12-19T19:07:58Z

Some time back, nfsd switched from calling vfs_fsync() to using a new commit_metadata() hook in export_operations(). If the file system did not provide a commit_metadata() hook, it fell back to using sync_inode_metadata(). Unfortunately doesn't work on all file systems. In particular, it doesn't work on ext4 due to how the inode gets journalled --- the VFS writeback code will not always call ext4_write_inode(). So we need to provide our own ext4_nfs_commit_metdata() method which calls ext4_write_inode() directly. Google-Bug-Id: 121195940 Signed-off-by: Theodore Ts'o Cc: stable@kernel.org

ext4: adjust reserved cluster count when removing extents

2018-10-01T18:25:08Z

Modify ext4_ext_remove_space() and the code it calls to correct the reserved cluster count for pending reservations (delayed allocated clusters shared with allocated blocks) when a block range is removed from the extent tree. Pending reservations may be found for the clusters at the ends of written or unwritten extents when a block range is removed. If a physical cluster at the end of an extent is freed, it's necessary to increment the reserved cluster count to maintain correct accounting if the corresponding logical cluster is shared with at least one delayed and unwritten extent as found in the extents status tree. Add a new function, ext4_rereserve_cluster(), to reapply a reservation on a delayed allocated cluster sharing blocks with a freed allocated cluster. To avoid ENOSPC on reservation, a flag is applied to ext4_free_blocks() to briefly defer updating the freeclusters counter when an allocated cluster is freed. This prevents another thread from allocating the freed block before the reservation can be reapplied. Redefine the partial cluster object as a struct to carry more state information and to clarify the code using it. Adjust the conditional code structure in ext4_ext_remove_space to reduce the indentation level in the main body of the code to improve readability. Signed-off-by: Eric Whitney Signed-off-by: Theodore Ts'o

ext4: fix reserved cluster accounting at delayed write time

2018-10-01T18:19:37Z

The code in ext4_da_map_blocks sometimes reserves space for more delayed allocated clusters than it should, resulting in premature ENOSPC, exceeded quota, and inaccurate free space reporting. Fix this by checking for written and unwritten blocks shared in the same cluster with the newly delayed allocated block. A cluster reservation should not be made for a cluster for which physical space has already been allocated. Signed-off-by: Eric Whitney Signed-off-by: Theodore Ts'o