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* ext4: split IOMAP_WRITE branch in ext4_iomap_begin() into helperMatthew Bobrowski2019-11-051-52/+61
| | | | | | | | | | | | | | | In preparation for porting across the ext4 direct I/O path over to the iomap infrastructure, split up the IOMAP_WRITE branch that's currently within ext4_iomap_begin() into a separate helper ext4_alloc_iomap(). This way, when we add in the necessary code for direct I/O, we don't end up with ext4_iomap_begin() becoming a monstrous twisty maze. Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/50eef383add1ea529651640574111076c55aca9f.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: move set iomap routines into a separate helper ext4_set_iomap()Matthew Bobrowski2019-11-051-42/+48
| | | | | | | | | | | | | | Separate the iomap field population code that is currently within ext4_iomap_begin() into a separate helper ext4_set_iomap(). The intent of this function is self explanatory, however the rationale behind taking this step is to reeduce the overall clutter that we currently have within the ext4_iomap_begin() callback. Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/1ea34da65eecffcddffb2386668ae06134e8deaf.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: iomap that extends beyond EOF should be marked dirtyMatthew Bobrowski2019-11-051-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch addresses what Dave Chinner had discovered and fixed within commit: 7684e2c4384d. This changes does not have any user visible impact for ext4 as none of the current users of ext4_iomap_begin() that extend files depend on IOMAP_F_DIRTY. When doing a direct IO that spans the current EOF, and there are written blocks beyond EOF that extend beyond the current write, the only metadata update that needs to be done is a file size extension. However, we don't mark such iomaps as IOMAP_F_DIRTY to indicate that there is IO completion metadata updates required, and hence we may fail to correctly sync file size extensions made in IO completion when O_DSYNC writes are being used and the hardware supports FUA. Hence when setting IOMAP_F_DIRTY, we need to also take into account whether the iomap spans the current EOF. If it does, then we need to mark it dirty so that IO completion will call generic_write_sync() to flush the inode size update to stable storage correctly. Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/8b43ee9ee94bee5328da56ba0909b7d2229ef150.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: update direct I/O read lock pattern for IOCB_NOWAITMatthew Bobrowski2019-11-051-1/+7
| | | | | | | | | | | | | | This patch updates the lock pattern in ext4_direct_IO_read() to not block on inode lock in cases of IOCB_NOWAIT direct I/O reads. The locking condition implemented here is similar to that of 942491c9e6d6 ("xfs: fix AIM7 regression"). Fixes: 16c54688592c ("ext4: Allow parallel DIO reads") Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/c5d5e759f91747359fbd2c6f9a36240cf75ad79f.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: reorder map.m_flags checks within ext4_iomap_begin()Matthew Bobrowski2019-11-051-3/+13
| | | | | | | | | | | | | | | | | | | | | | | For the direct I/O changes that follow in this patch series, we need to accommodate for the case where the block mapping flags passed through to ext4_map_blocks() result in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits set. In order for any allocated unwritten extents to be converted correctly in the ->end_io() handler, the iomap->type must be set to IOMAP_UNWRITTEN for cases where the EXT4_MAP_UNWRITTEN bit has been set within m_flags. Hence the reason why we need to reshuffle this conditional statement around. This change is a no-op for DAX as the block mapping flags passed through to ext4_map_blocks() i.e. EXT4_GET_BLOCKS_CREATE_ZERO never results in both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN being set at once. Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/1309ad80d31a637b2deed55a85283d582a54a26a.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* Merge branch 'iomap-for-next' into mb/dioTheodore Ts'o2019-11-0526-915/+1086
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| * fs/iomap: remove redundant check in iomap_dio_rw()Joseph Qi2019-10-291-1/+1
| | | | | | | | | | | | | | | | | | | | We've already check if it is READ iov_iter, no need check again. Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: use a srcmap for a read-modify-write I/OGoldwyn Rodrigues2019-10-2112-55/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The srcmap is used to identify where the read is to be performed from. It is passed to ->iomap_begin, which can fill it in if we need to read data for partially written blocks from a different location than the write target. The srcmap is only supported for buffered writes so far. Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> [hch: merged two patches, removed the IOMAP_F_COW flag, use iomap as srcmap if not set, adjust length down to srcmap end as well] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Acked-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
| * iomap: renumber IOMAP_HOLE to 0Christoph Hellwig2019-10-211-5/+5
| | | | | | | | | | | | | | | | | | | | | | Instead of keeping a separate unnamed state for uninitialized iomaps, renumber IOMAP_HOLE to zero so that an uninitialized iomap is treated as a hole. Suggested-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: use write_begin to read pages to unshareChristoph Hellwig2019-10-211-33/+16
| | | | | | | | | | | | | | | | | | | | Use the existing iomap write_begin code to read the pages unshared by iomap_file_unshare. That avoids the extra ->readpage call and extent tree lookup currently done by read_mapping_page. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: move the zeroing case out of iomap_read_page_syncChristoph Hellwig2019-10-211-17/+16
| | | | | | | | | | | | | | | | | | That keeps the function a little easier to understand, and easier to modify for pending enhancements. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: ignore non-shared or non-data blocks in xfs_file_dirtyChristoph Hellwig2019-10-213-6/+13
| | | | | | | | | | | | | | | | | | | | | | xfs_file_dirty is used to unshare reflink blocks. Rename the function to xfs_file_unshare to better document that purpose, and skip iomaps that are not shared and don't need zeroing. This will allow to simplify the caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: always use AOP_FLAG_NOFS in iomap_write_beginChristoph Hellwig2019-10-211-9/+5
| | | | | | | | | | | | | | | | | | | | All callers pass AOP_FLAG_NOFS, so lift that flag to iomap_write_begin to allow reusing the flags arguments for an internal flags namespace soon. Also remove the local index variable that is only used once. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: remove the unused iomap argument to __iomap_write_endChristoph Hellwig2019-10-211-2/+2
| | | | | | | | | | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Allison Collins <allison.henderson@oracle.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: better document the IOMAP_F_* flagsChristoph Hellwig2019-10-211-8/+23
| | | | | | | | | | | | | | | | | | | | | | | | The documentation for IOMAP_F_* is a bit disorganized, and doesn't mention the fact that most flags are set by the file system and consumed by the iomap core, while IOMAP_F_SIZE_CHANGED is set by the core and consumed by the file system. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Allison Collins <allison.henderson@oracle.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: enhance writeback error messageDarrick J. Wong2019-10-211-2/+3
| | | | | | | | | | | | | | | | | | | | If we encounter an IO error during writeback, log the inode, offset, and sector number of the failure, instead of forcing the user to do some sort of reverse mapping to figure out which file is affected. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
| * iomap: pass a struct page to iomap_finish_page_writebackChristoph Hellwig2019-10-211-5/+5
| | | | | | | | | | | | | | | | No need to pass the full bio_vec. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: cleanup iomap_ioend_compareChristoph Hellwig2019-10-211-4/+3
| | | | | | | | | | | | | | | | | | | | Move the initialization of ia and ib to the declaration line and remove a superflous else. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: move struct iomap_page out of iomap.hChristoph Hellwig2019-10-212-17/+17
| | | | | | | | | | | | | | | | | | | | | | Now that all the writepage code is in the iomap code there is no need to keep this structure public. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: warn on inline maps in iomap_writepage_mapChristoph Hellwig2019-10-211-0/+2
| | | | | | | | | | | | | | | | | | | | And inline mapping should never mark the page dirty and thus never end up in writepages. Add a check for that condition and warn if it happens. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: lift the xfs writeback code to iomapChristoph Hellwig2019-10-217-648/+669
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Take the xfs writeback code and move it to fs/iomap. A new structure with three methods is added as the abstraction from the generic writeback code to the file system. These methods are used to map blocks, submit an ioend, and cancel a page that encountered an error before it was added to an ioend. Signed-off-by: Christoph Hellwig <hch@lst.de> [darrick: rename ->submit_ioend to ->prepare_ioend to clarify what it does] Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
| * iomap: lift common tracing code from xfs to iomapChristoph Hellwig2019-10-216-57/+120
| | | | | | | | | | | | | | | | | | | | Lift the xfs code for tracing address space operations to the iomap layer. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: zero newly allocated mapped blocksChristoph Hellwig2019-10-211-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | File systems like gfs2 don't support delayed allocations or unwritten extents and thus allocate normal mapped blocks to fill holes. To cover the case of such file systems allocating new blocks to fill holes also zero out mapped blocks with the new flag. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * xfs: remove the fork fields in the writepage_ctx and ioendChristoph Hellwig2019-10-212-27/+46
| | | | | | | | | | | | | | | | | | | | In preparation for moving the writeback code to iomap.c, replace the XFS-specific COW fork concept with the iomap IOMAP_F_SHARED flag. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * xfs: turn io_append_trans into an io_private void pointerChristoph Hellwig2019-10-212-14/+14
| | | | | | | | | | | | | | | | | | | | | | In preparation for moving the ioend structure to common code we need to get rid of the xfs-specific xfs_trans type. Just make it a file system private void pointer instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * xfs: refactor the ioend merging codeChristoph Hellwig2019-10-211-31/+42
| | | | | | | | | | | | | | | | | | | | | | Introduce two nicely abstracted helper, which can be moved to the iomap code later. Also use list_first_entry_or_null to simplify the code a bit. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * xfs: use a struct iomap in xfs_writepage_ctxChristoph Hellwig2019-10-214-51/+50
| | | | | | | | | | | | | | | | | | | | | | In preparation for moving the XFS writeback code to fs/iomap.c, switch it to use struct iomap instead of the XFS-specific struct xfs_bmbt_irec. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * xfs: set IOMAP_F_NEW more carefullyChristoph Hellwig2019-10-211-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | Don't set IOMAP_F_NEW if we COW over an existing allocated range, as these aren't strictly new allocations. This is required to be able to use IOMAP_F_NEW to zero newly allocated blocks, which is required for the iomap code to fully support file systems that don't do delayed allocations or use unwritten extents. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * xfs: initialize iomap->flags in xfs_bmbt_to_iomapChristoph Hellwig2019-10-213-14/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | Currently we don't overwrite the flags field in the iomap in xfs_bmbt_to_iomap. This works fine with 0-initialized iomaps on stack, but is harmful once we want to be able to reuse an iomap in the writeback code. Replace the shared parameter with a set of initial flags an thus ensures the flags field is always reinitialized. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: iomap that extends beyond EOF should be marked dirtyDave Chinner2019-10-172-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When doing a direct IO that spans the current EOF, and there are written blocks beyond EOF that extend beyond the current write, the only metadata update that needs to be done is a file size extension. However, we don't mark such iomaps as IOMAP_F_DIRTY to indicate that there is IO completion metadata updates required, and hence we may fail to correctly sync file size extensions made in IO completion when O_DSYNC writes are being used and the hardware supports FUA. Hence when setting IOMAP_F_DIRTY, we need to also take into account whether the iomap spans the current EOF. If it does, then we need to mark it dirty so that IO completion will call generic_write_sync() to flush the inode size update to stable storage correctly. Fixes: 3460cac1ca76 ("iomap: Use FUA for pure data O_DSYNC DIO writes") Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> [darrick: removed the ext4 part; they'll handle it separately] Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * xfs: Use iomap_dio_rw to wait for unaligned direct IOJan Kara2019-10-151-8/+4
| | | | | | | | | | | | | | | | | | Use iomap_dio_rw() to wait for unaligned direct IO instead of opencoding the wait. Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
| * iomap: Allow forcing of waiting for running DIO in iomap_dio_rw()Jan Kara2019-10-154-7/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Filesystems do not support doing IO as asynchronous in some cases. For example in case of unaligned writes or in case file size needs to be extended (e.g. for ext4). Instead of forcing filesystem to wait for AIO in such cases, add argument to iomap_dio_rw() which makes the function wait for IO completion. This also results in executing iomap_dio_complete() inline in iomap_dio_rw() providing its return value to the caller as for ordinary sync IO. Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
* | Merge branch 'rh/dioread-nolock-1k' into devTheodore Ts'o2019-11-015-110/+208
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| * | ext4: Enable blocksize < pagesize for dioread_nolockRitesh Harjani2019-10-221-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All support is now added for blocksize < pagesize for dioread_nolock. This patch removes those checks which disables dioread_nolock feature for blocksize != pagesize. Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191016073711.4141-6-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * | ext4: Add support for blocksize < pagesize in dioread_nolockRitesh Harjani2019-10-224-29/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds the support for blocksize < pagesize for dioread_nolock feature. Since in case of blocksize < pagesize, we can have multiple small buffers of page as unwritten extents, we need to maintain a vector of these unwritten extents which needs the conversion after the IO is complete. Thus, we maintain a list of tuple <offset, size> pair (io_end_vec) for this & traverse this list to do the unwritten to written conversion. Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191016073711.4141-5-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * | ext4: Refactor mpage_map_and_submit_buffers functionRitesh Harjani2019-10-221-42/+83
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch refactors mpage_map_and_submit_buffers to take out the page buffers processing, as a separate function. This will be required to add support for blocksize < pagesize for dioread_nolock feature. No functionality change in this patch. Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191016073711.4141-4-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * | ext4: Add API to bring in support for unwritten io_end_vec conversionRitesh Harjani2019-10-223-19/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch just brings in the API for conversion of unwritten io_end_vec extents which will be required for blocksize < pagesize support for dioread_nolock feature. No functional changes in this patch. Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191016073711.4141-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| * | ext4: keep uniform naming convention for io & io_end variablesRitesh Harjani2019-10-221-27/+28
| |/ | | | | | | | | | | | | | | | | | | Let's keep uniform naming convention for ext4_submit_io (io) & ext4_end_io_t (io_end) structures, to avoid any confusion. No functionality change in this patch. Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191016073711.4141-2-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | jbd2: Free journal head outside of locked regionThomas Gleixner2019-10-211-6/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On PREEMPT_RT bit-spinlocks have the same semantics as on PREEMPT_RT=n, i.e. they disable preemption. That means functions which are not safe to be called in preempt disabled context on RT trigger a might_sleep() assert. The journal head bit spinlock is mostly held for short code sequences with trivial RT safe functionality, except for one place: jbd2_journal_put_journal_head() invokes __journal_remove_journal_head() with the journal head bit spinlock held. __journal_remove_journal_head() invokes kmem_cache_free() which must not be called with preemption disabled on RT. Jan suggested to rework the removal function so the actual free happens outside the bit-spinlocked region. Split it into two parts: - Do the sanity checks and the buffer head detach under the lock - Do the actual free after dropping the lock There is error case handling in the free part which needs to dereference the b_size field of the now detached buffer head. Due to paranoia (caused by ignorance) the size is retrieved in the detach function and handed into the free function. Might be over-engineered, but better safe than sorry. This makes the journal head bit-spinlock usage RT compliant and also avoids nested locking which is not covered by lockdep. Suggested-by: Jan Kara <jack@suse.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-ext4@vger.kernel.org Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan Kara <jack@suse.com> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20190809124233.13277-8-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | jbd2: Make state lock a spinlockThomas Gleixner2019-10-216-94/+84
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Bit-spinlocks are problematic on PREEMPT_RT if functions which might sleep on RT, e.g. spin_lock(), alloc/free(), are invoked inside the lock held region because bit spinlocks disable preemption even on RT. A first attempt was to replace state lock with a spinlock placed in struct buffer_head and make the locking conditional on PREEMPT_RT and DEBUG_BIT_SPINLOCKS. Jan pointed out that there is a 4 byte hole in struct journal_head where a regular spinlock fits in and he would not object to convert the state lock to a spinlock unconditionally. Aside of solving the RT problem, this also gains lockdep coverage for the journal head state lock (bit-spinlocks are not covered by lockdep as it's hard to fit a lockdep map into a single bit). The trivial change would have been to convert the jbd_*lock_bh_state() inlines, but that comes with the downside that these functions take a buffer head pointer which needs to be converted to a journal head pointer which adds another level of indirection. As almost all functions which use this lock have a journal head pointer readily available, it makes more sense to remove the lock helper inlines and write out spin_*lock() at all call sites. Fixup all locking comments as well. Suggested-by: Jan Kara <jack@suse.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jan Kara <jack@suse.cz> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Jan Kara <jack@suse.com> Cc: linux-ext4@vger.kernel.org Link: https://lore.kernel.org/r/20190809124233.13277-7-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | jbd2: Don't call __bforget() unnecessarilyJan Kara2019-10-211-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | jbd2_journal_forget() jumps to 'not_jbd' branch which calls __bforget() in cases where the buffer is clean which is pointless. In case of failed assertion, it can be even argued that it is safer not to touch buffer's dirty bits. Also logically it makes more sense to just jump to 'drop' and that will make logic also simpler when we switch bh_state_lock to a spinlock. Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20190809124233.13277-6-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | jbd2: Drop unnecessary branch from jbd2_journal_forget()Jan Kara2019-10-211-4/+0
| | | | | | | | | | | | | | | | | | | | We have cleared both dirty & jbddirty bits from the bh. So there's no difference between bforget() and brelse(). Thus there's no point jumping to no_jbd branch. Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20190809124233.13277-5-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | jbd2: Move dropping of jh reference out of un/re-filing functionsJan Kara2019-10-213-10/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | __jbd2_journal_unfile_buffer() and __jbd2_journal_refile_buffer() drop transaction's jh reference when they remove jh from a transaction. This will be however inconvenient once we move state lock into journal_head itself as we still need to unlock it and we'd need to grab jh reference just for that. Move dropping of jh reference out of these functions into the few callers. Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20190809124233.13277-4-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | jbd2: Remove jbd_trylock_bh_state()Thomas Gleixner2019-10-211-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | No users. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Jan Kara <jack@suse.cz> Cc: linux-ext4@vger.kernel.org Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20190809124233.13277-3-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* | jbd2: Simplify journal_unmap_buffer()Thomas Gleixner2019-10-211-6/+2
|/ | | | | | | | | | | | | | | | | | | | | | journal_unmap_buffer() checks first whether the buffer head is a journal. If so it takes locks and then invokes jbd2_journal_grab_journal_head() followed by another check whether this is journal head buffer. The double checking is pointless. Replace the initial check with jbd2_journal_grab_journal_head() which alredy checks whether the buffer head is actually a journal. Allows also early access to the journal head pointer for the upcoming conversion of state lock to a regular spinlock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Jan Kara <jack@suse.cz> Cc: linux-ext4@vger.kernel.org Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20190809124233.13277-2-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* Linux 5.4-rc3v5.4-rc3Linus Torvalds2019-10-141-1/+1
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* Merge tag 'trace-v5.4-rc2' of ↵Linus Torvalds2019-10-1315-132/+223
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: "A few tracing fixes: - Remove lockdown from tracefs itself and moved it to the trace directory. Have the open functions there do the lockdown checks. - Fix a few races with opening an instance file and the instance being deleted (Discovered during the lockdown updates). Kept separate from the clean up code such that they can be backported to stable easier. - Clean up and consolidated the checks done when opening a trace file, as there were multiple checks that need to be done, and it did not make sense having them done in each open instance. - Fix a regression in the record mcount code. - Small hw_lat detector tracer fixes. - A trace_pipe read fix due to not initializing trace_seq" * tag 'trace-v5.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Initialize iter->seq after zeroing in tracing_read_pipe() tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency tracing/hwlat: Report total time spent in all NMIs during the sample recordmcount: Fix nop_mcount() function tracing: Do not create tracefs files if tracefs lockdown is in effect tracing: Add locked_down checks to the open calls of files created for tracefs tracing: Add tracing_check_open_get_tr() tracing: Have trace events system open call tracing_open_generic_tr() tracing: Get trace_array reference for available_tracers files ftrace: Get a reference counter for the trace_array on filter files tracefs: Revert ccbd54ff54e8 ("tracefs: Restrict tracefs when the kernel is locked down")
| * tracing: Initialize iter->seq after zeroing in tracing_read_pipe()Petr Mladek2019-10-131-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A customer reported the following softlockup: [899688.160002] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [test.sh:16464] [899688.160002] CPU: 0 PID: 16464 Comm: test.sh Not tainted 4.12.14-6.23-azure #1 SLE12-SP4 [899688.160002] RIP: 0010:up_write+0x1a/0x30 [899688.160002] Kernel panic - not syncing: softlockup: hung tasks [899688.160002] RIP: 0010:up_write+0x1a/0x30 [899688.160002] RSP: 0018:ffffa86784d4fde8 EFLAGS: 00000257 ORIG_RAX: ffffffffffffff12 [899688.160002] RAX: ffffffff970fea00 RBX: 0000000000000001 RCX: 0000000000000000 [899688.160002] RDX: ffffffff00000001 RSI: 0000000000000080 RDI: ffffffff970fea00 [899688.160002] RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000 [899688.160002] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8b59014720d8 [899688.160002] R13: ffff8b59014720c0 R14: ffff8b5901471090 R15: ffff8b5901470000 [899688.160002] tracing_read_pipe+0x336/0x3c0 [899688.160002] __vfs_read+0x26/0x140 [899688.160002] vfs_read+0x87/0x130 [899688.160002] SyS_read+0x42/0x90 [899688.160002] do_syscall_64+0x74/0x160 It caught the process in the middle of trace_access_unlock(). There is no loop. So, it must be looping in the caller tracing_read_pipe() via the "waitagain" label. Crashdump analyze uncovered that iter->seq was completely zeroed at this point, including iter->seq.seq.size. It means that print_trace_line() was never able to print anything and there was no forward progress. The culprit seems to be in the code: /* reset all but tr, trace, and overruns */ memset(&iter->seq, 0, sizeof(struct trace_iterator) - offsetof(struct trace_iterator, seq)); It was added by the commit 53d0aa773053ab182877 ("ftrace: add logic to record overruns"). It was v2.6.27-rc1. It was the time when iter->seq looked like: struct trace_seq { unsigned char buffer[PAGE_SIZE]; unsigned int len; }; There was no "size" variable and zeroing was perfectly fine. The solution is to reinitialize the structure after or without zeroing. Link: http://lkml.kernel.org/r/20191011142134.11997-1-pmladek@suse.com Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing/hwlat: Don't ignore outer-loop duration when calculating max_latencySrivatsa S. Bhat (VMware)2019-10-131-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | max_latency is intended to record the maximum ever observed hardware latency, which may occur in either part of the loop (inner/outer). So we need to also consider the outer-loop sample when updating max_latency. Link: http://lkml.kernel.org/r/157073345463.17189.18124025522664682811.stgit@srivatsa-ubuntu Fixes: e7c15cd8a113 ("tracing: Added hardware latency tracer") Cc: stable@vger.kernel.org Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * tracing/hwlat: Report total time spent in all NMIs during the sampleSrivatsa S. Bhat (VMware)2019-10-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | nmi_total_ts is supposed to record the total time spent in *all* NMIs that occur on the given CPU during the (active portion of the) sampling window. However, the code seems to be overwriting this variable for each NMI, thereby only recording the time spent in the most recent NMI. Fix it by accumulating the duration instead. Link: http://lkml.kernel.org/r/157073343544.17189.13911783866738671133.stgit@srivatsa-ubuntu Fixes: 7b2c86250122 ("tracing: Add NMI tracing in hwlat detector") Cc: stable@vger.kernel.org Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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