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linux/fs/xfs/xfs_reflink.h

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xfs: convert to SPDX license tags Remove the verbose license text from XFS files and replace them with SPDX tags. This does not change the license of any of the code, merely refers to the common, up-to-date license files in LICENSES/ This change was mostly scripted. fs/xfs/Makefile and fs/xfs/libxfs/xfs_fs.h were modified by hand, the rest were detected and modified by the following command: for f in `git grep -l "GNU General" fs/xfs/` ; do echo $f cat $f | awk -f hdr.awk > $f.new mv -f $f.new $f done And the hdr.awk script that did the modification (including detecting the difference between GPL-2.0 and GPL-2.0+ licenses) is as follows: $ cat hdr.awk BEGIN { hdr = 1.0 tag = "GPL-2.0" str = "" } /^ \* This program is free software/ { hdr = 2.0; next } /any later version./ { tag = "GPL-2.0+" next } /^ \*\// { if (hdr > 0.0) { print "// SPDX-License-Identifier: " tag print str print $0 str="" hdr = 0.0 next } print $0 next } /^ \* / { if (hdr > 1.0) next if (hdr > 0.0) { if (str != "") str = str "\n" str = str $0 next } print $0 next } /^ \*/ { if (hdr > 0.0) next print $0 next } // { if (hdr > 0.0) { if (str != "") str = str "\n" str = str $0 next } print $0 } END { } $ Signed-off-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>
2018-06-06 10:42:14 +08:00
// SPDX-License-Identifier: GPL-2.0+
xfs: introduce the CoW fork Introduce a new in-core fork for storing copy-on-write delalloc reservations and allocated extents that are in the process of being written out. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:32 +08:00
/*
* Copyright (C) 2016 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*/
#ifndef __XFS_REFLINK_H
#define __XFS_REFLINK_H 1
xfs: introduce an always_cow mode Add a mode where XFS never overwrites existing blocks in place. This is to aid debugging our COW code, and also put infatructure in place for things like possible future support for zoned block devices, which can't support overwrites. This mode is enabled globally by doing a: echo 1 > /sys/fs/xfs/debug/always_cow Note that the parameter is global to allow running all tests in xfstests easily in this mode, which would not easily be possible with a per-fs sysfs file. In always_cow mode persistent preallocations are disabled, and fallocate will fail when called with a 0 mode (with our without FALLOC_FL_KEEP_SIZE), and not create unwritten extent for zeroed space when called with FALLOC_FL_ZERO_RANGE or FALLOC_FL_UNSHARE_RANGE. There are a few interesting xfstests failures when run in always_cow mode: - generic/392 fails because the bytes used in the file used to test hole punch recovery are less after the log replay. This is because the blocks written and then punched out are only freed with a delay due to the logging mechanism. - xfs/170 will fail as the already fragile file streams mechanism doesn't seem to interact well with the COW allocator - xfs/180 xfs/182 xfs/192 xfs/198 xfs/204 and xfs/208 will claim the file system is badly fragmented, but there is not much we can do to avoid that when always writing out of place - xfs/205 fails because overwriting a file in always_cow mode will require new space allocation and the assumption in the test thus don't work anymore. - xfs/326 fails to modify the file at all in always_cow mode after injecting the refcount error, leading to an unexpected md5sum after the remount, but that again is expected 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>
2019-02-19 01:38:49 +08:00
static inline bool xfs_is_always_cow_inode(struct xfs_inode *ip)
{
return ip->i_mount->m_always_cow &&
xfs_sb_version_hasreflink(&ip->i_mount->m_sb);
}
static inline bool xfs_is_cow_inode(struct xfs_inode *ip)
{
return xfs_is_reflink_inode(ip) || xfs_is_always_cow_inode(ip);
}
xfs: reflink find shared should take a transaction Adapt _reflink_find_shared to take an optional transaction pointer. The inode scrubber code will need to decide (within transaction context) if a file has shared blocks. To avoid buffer deadlocks, we must pass the tp through to this function's utility calls. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-17 02:00:10 +08:00
extern int xfs_reflink_find_shared(struct xfs_mount *mp, struct xfs_trans *tp,
xfs_agnumber_t agno, xfs_agblock_t agbno, xfs_extlen_t aglen,
xfs_agblock_t *fbno, xfs_extlen_t *flen, bool find_maximal);
xfs: create delalloc extents in CoW fork Wire up iomap_begin to detect shared extents and create delayed allocation extents in the CoW fork: 1) Check if we already have an extent in the COW fork for the area. If so nothing to do, we can move along. 2) Look up block number for the current extent, and if there is none it's not shared move along. 3) Unshare the current extent as far as we are going to write into it. For this we avoid an additional COW fork lookup and use the information we set aside in step 1) above. 4) Goto 1) unless we've covered the whole range. Last but not least, this updates the xfs_reflink_reserve_cow_range calling convention to pass a byte offset and length, as that is what both callers expect anyway. This patch has been refactored considerably as part of the iomap transition. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:33 +08:00
extern int xfs_reflink_trim_around_shared(struct xfs_inode *ip,
xfs: remove the unused trimmed argument from xfs_reflink_trim_around_shared Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-18 14:19:48 +08:00
struct xfs_bmbt_irec *irec, bool *shared);
xfs: introduce an always_cow mode Add a mode where XFS never overwrites existing blocks in place. This is to aid debugging our COW code, and also put infatructure in place for things like possible future support for zoned block devices, which can't support overwrites. This mode is enabled globally by doing a: echo 1 > /sys/fs/xfs/debug/always_cow Note that the parameter is global to allow running all tests in xfstests easily in this mode, which would not easily be possible with a per-fs sysfs file. In always_cow mode persistent preallocations are disabled, and fallocate will fail when called with a 0 mode (with our without FALLOC_FL_KEEP_SIZE), and not create unwritten extent for zeroed space when called with FALLOC_FL_ZERO_RANGE or FALLOC_FL_UNSHARE_RANGE. There are a few interesting xfstests failures when run in always_cow mode: - generic/392 fails because the bytes used in the file used to test hole punch recovery are less after the log replay. This is because the blocks written and then punched out are only freed with a delay due to the logging mechanism. - xfs/170 will fail as the already fragile file streams mechanism doesn't seem to interact well with the COW allocator - xfs/180 xfs/182 xfs/192 xfs/198 xfs/204 and xfs/208 will claim the file system is badly fragmented, but there is not much we can do to avoid that when always writing out of place - xfs/205 fails because overwriting a file in always_cow mode will require new space allocation and the assumption in the test thus don't work anymore. - xfs/326 fails to modify the file at all in always_cow mode after injecting the refcount error, leading to an unexpected md5sum after the remount, but that again is expected 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>
2019-02-19 01:38:49 +08:00
bool xfs_inode_need_cow(struct xfs_inode *ip, struct xfs_bmbt_irec *imap,
bool *shared);
xfs: create delalloc extents in CoW fork Wire up iomap_begin to detect shared extents and create delayed allocation extents in the CoW fork: 1) Check if we already have an extent in the COW fork for the area. If so nothing to do, we can move along. 2) Look up block number for the current extent, and if there is none it's not shared move along. 3) Unshare the current extent as far as we are going to write into it. For this we avoid an additional COW fork lookup and use the information we set aside in step 1) above. 4) Goto 1) unless we've covered the whole range. Last but not least, this updates the xfs_reflink_reserve_cow_range calling convention to pass a byte offset and length, as that is what both callers expect anyway. This patch has been refactored considerably as part of the iomap transition. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:33 +08:00
xfs: pass two imaps to xfs_reflink_allocate_cow xfs_reflink_allocate_cow consumes the source data fork imap, and potentially returns the COW fork imap. Split the arguments in two to clear up the calling conventions and to prepare for returning a source iomap from ->iomap_begin. 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>
2019-10-20 00:09:43 +08:00
int xfs_reflink_allocate_cow(struct xfs_inode *ip, struct xfs_bmbt_irec *imap,
struct xfs_bmbt_irec *cmap, bool *shared, uint *lockmode,
xfs: don't pass iomap flags to xfs_reflink_allocate_cow Don't pass raw iomap flags to xfs_reflink_allocate_cow; signal our intention with a boolean argument. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2019-02-22 08:26:35 +08:00
bool convert_now);
xfs: mark speculative prealloc CoW fork extents unwritten Christoph Hellwig pointed out that there's a potentially nasty race when performing simultaneous nearby directio cow writes: "Thread 1 writes a range from B to c " B --------- C p "a little later thread 2 writes from A to B " A --------- B p [editor's note: the 'p' denote cowextsize boundaries, which I added to make this more clear] "but the code preallocates beyond B into the range where thread "1 has just written, but ->end_io hasn't been called yet. "But once ->end_io is called thread 2 has already allocated "up to the extent size hint into the write range of thread 1, "so the end_io handler will splice the unintialized blocks from "that preallocation back into the file right after B." We can avoid this race by ensuring that thread 1 cannot accidentally remap the blocks that thread 2 allocated (as part of speculative preallocation) as part of t2's write preparation in t1's end_io handler. The way we make this happen is by taking advantage of the unwritten extent flag as an intermediate step. Recall that when we begin the process of writing data to shared blocks, we create a delayed allocation extent in the CoW fork: D: --RRRRRRSSSRRRRRRRR--- C: ------DDDDDDD--------- When a thread prepares to CoW some dirty data out to disk, it will now convert the delalloc reservation into an /unwritten/ allocated extent in the cow fork. The da conversion code tries to opportunistically allocate as much of a (speculatively prealloc'd) extent as possible, so we may end up allocating a larger extent than we're actually writing out: D: --RRRRRRSSSRRRRRRRR--- U: ------UUUUUUU--------- Next, we convert only the part of the extent that we're actively planning to write to normal (i.e. not unwritten) status: D: --RRRRRRSSSRRRRRRRR--- U: ------UURRUUU--------- If the write succeeds, the end_cow function will now scan the relevant range of the CoW fork for real extents and remap only the real extents into the data fork: D: --RRRRRRRRSRRRRRRRR--- U: ------UU--UUU--------- This ensures that we never obliterate valid data fork extents with unwritten blocks from the CoW fork. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2017-02-03 07:14:02 +08:00
extern int xfs_reflink_convert_cow(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t count);
xfs: create delalloc extents in CoW fork Wire up iomap_begin to detect shared extents and create delayed allocation extents in the CoW fork: 1) Check if we already have an extent in the COW fork for the area. If so nothing to do, we can move along. 2) Look up block number for the current extent, and if there is none it's not shared move along. 3) Unshare the current extent as far as we are going to write into it. For this we avoid an additional COW fork lookup and use the information we set aside in step 1) above. 4) Goto 1) unless we've covered the whole range. Last but not least, this updates the xfs_reflink_reserve_cow_range calling convention to pass a byte offset and length, as that is what both callers expect anyway. This patch has been refactored considerably as part of the iomap transition. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:33 +08:00
xfs: move mappings from cow fork to data fork after copy-write After the write component of a copy-write operation finishes, clean up the bookkeeping left behind. On error, we simply free the new blocks and pass the error up. If we succeed, however, then we must remove the old data fork mapping and move the cow fork mapping to the data fork. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [hch: Call the CoW failure function during xfs_cancel_ioend] Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:35 +08:00
extern int xfs_reflink_cancel_cow_blocks(struct xfs_inode *ip,
struct xfs_trans **tpp, xfs_fileoff_t offset_fsb,
xfs: only reclaim unwritten COW extents periodically We only want to reclaim preallocations from our periodic work item. Currently this is archived by looking for a dirty inode, but that check is rather fragile. Instead add a flag to xfs_reflink_cancel_cow_* so that the caller can ask for just cancelling unwritten extents in the COW fork. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> [darrick: fix typos in commit message] Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-03-08 08:45:58 +08:00
xfs_fileoff_t end_fsb, bool cancel_real);
xfs: move mappings from cow fork to data fork after copy-write After the write component of a copy-write operation finishes, clean up the bookkeeping left behind. On error, we simply free the new blocks and pass the error up. If we succeed, however, then we must remove the old data fork mapping and move the cow fork mapping to the data fork. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [hch: Call the CoW failure function during xfs_cancel_ioend] Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:35 +08:00
extern int xfs_reflink_cancel_cow_range(struct xfs_inode *ip, xfs_off_t offset,
xfs: only reclaim unwritten COW extents periodically We only want to reclaim preallocations from our periodic work item. Currently this is archived by looking for a dirty inode, but that check is rather fragile. Instead add a flag to xfs_reflink_cancel_cow_* so that the caller can ask for just cancelling unwritten extents in the COW fork. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> [darrick: fix typos in commit message] Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-03-08 08:45:58 +08:00
xfs_off_t count, bool cancel_real);
xfs: move mappings from cow fork to data fork after copy-write After the write component of a copy-write operation finishes, clean up the bookkeeping left behind. On error, we simply free the new blocks and pass the error up. If we succeed, however, then we must remove the old data fork mapping and move the cow fork mapping to the data fork. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [hch: Call the CoW failure function during xfs_cancel_ioend] Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:35 +08:00
extern int xfs_reflink_end_cow(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t count);
xfs: store in-progress CoW allocations in the refcount btree Due to the way the CoW algorithm in XFS works, there's an interval during which blocks allocated to handle a CoW can be lost -- if the FS goes down after the blocks are allocated but before the block remapping takes place. This is exacerbated by the cowextsz hint -- allocated reservations can sit around for a while, waiting to get used. Since the refcount btree doesn't normally store records with refcount of 1, we can use it to record these in-progress extents. In-progress blocks cannot be shared because they're not user-visible, so there shouldn't be any conflicts with other programs. This is a better solution than holding EFIs during writeback because (a) EFIs can't be relogged currently, (b) even if they could, EFIs are bound by available log space, which puts an unnecessary upper bound on how much CoW we can have in flight, and (c) we already have a mechanism to track blocks. At mount time, read the refcount records and free anything we find with a refcount of 1 because those were in-progress when the FS went down. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:39 +08:00
extern int xfs_reflink_recover_cow(struct xfs_mount *mp);
xfs: support returning partial reflink results Back when the XFS reflink code only supported clone_file_range, we were only able to return zero or negative error codes to userspace. However, now that copy_file_range (which returns bytes copied) can use XFS' clone_file_range, we have the opportunity to return partial results. For example, if userspace sends a 1GB clone request and we run out of space halfway through, we at least can tell userspace that we completed 512M of that request like a regular write. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30 07:47:06 +08:00
extern loff_t xfs_reflink_remap_range(struct file *file_in, loff_t pos_in,
vfs: make remap_file_range functions take and return bytes completed Change the remap_file_range functions to take a number of bytes to operate upon and return the number of bytes they operated on. This is a requirement for allowing fs implementations to return short clone/dedupe results to the user, which will enable us to obey resource limits in a graceful manner. A subsequent patch will enable copy_file_range to signal to the ->clone_file_range implementation that it can handle a short length, which will be returned in the function's return value. For now the short return is not implemented anywhere so the behavior won't change -- either copy_file_range manages to clone the entire range or it tries an alternative. Neither clone ioctl can take advantage of this, alas. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30 07:41:49 +08:00
struct file *file_out, loff_t pos_out, loff_t len,
vfs: pass remap flags to generic_remap_file_range_prep Plumb the remap flags through the filesystem from the vfs function dispatcher all the way to the prep function to prepare for behavior changes in subsequent patches. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30 07:41:28 +08:00
unsigned int remap_flags);
xfs: separate function to check if inode shares extents Separate the "clear reflink flag" function into one function that checks if the flag is needed, and a second function that checks and clears the flag. The inode scrub code will want to check the necessity of the flag without clearing it. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-17 02:00:11 +08:00
extern int xfs_reflink_inode_has_shared_extents(struct xfs_trans *tp,
struct xfs_inode *ip, bool *has_shared);
xfs: unshare a range of blocks via fallocate Unshare all shared extents if the user calls fallocate with the new unshare mode flag set, so that we can guarantee that a subsequent write will not ENOSPC. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [hch: pass inode instead of file to xfs_reflink_dirty_range, use iomap infrastructure for copy up] Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:43 +08:00
extern int xfs_reflink_clear_inode_flag(struct xfs_inode *ip,
struct xfs_trans **tpp);
extern int xfs_reflink_unshare(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t len);
xfs: remove xfs_reflink_remap_range Since xfs_file_remap_range is a thin wrapper, move the contents of xfs_reflink_remap_range into the shell. This cuts down on the vfs calls being made from internal xfs code. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30 07:47:26 +08:00
extern int xfs_reflink_remap_prep(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out, loff_t *len,
unsigned int remap_flags);
extern int xfs_reflink_remap_blocks(struct xfs_inode *src, loff_t pos_in,
struct xfs_inode *dest, loff_t pos_out, loff_t remap_len,
loff_t *remapped);
extern int xfs_reflink_update_dest(struct xfs_inode *dest, xfs_off_t newlen,
xfs_extlen_t cowextsize, unsigned int remap_flags);
extern void xfs_reflink_remap_unlock(struct file *file_in,
struct file *file_out);
xfs: move mappings from cow fork to data fork after copy-write After the write component of a copy-write operation finishes, clean up the bookkeeping left behind. On error, we simply free the new blocks and pass the error up. If we succeed, however, then we must remove the old data fork mapping and move the cow fork mapping to the data fork. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [hch: Call the CoW failure function during xfs_cancel_ioend] Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:35 +08:00
xfs: introduce the CoW fork Introduce a new in-core fork for storing copy-on-write delalloc reservations and allocated extents that are in the process of being written out. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-10-04 00:11:32 +08:00
#endif /* __XFS_REFLINK_H */
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