From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/btrfs/delalloc-space.c | 493 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 493 insertions(+) create mode 100644 fs/btrfs/delalloc-space.c (limited to 'fs/btrfs/delalloc-space.c') diff --git a/fs/btrfs/delalloc-space.c b/fs/btrfs/delalloc-space.c new file mode 100644 index 000000000..f2bc5563c --- /dev/null +++ b/fs/btrfs/delalloc-space.c @@ -0,0 +1,493 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "ctree.h" +#include "delalloc-space.h" +#include "block-rsv.h" +#include "btrfs_inode.h" +#include "space-info.h" +#include "transaction.h" +#include "qgroup.h" +#include "block-group.h" + +/* + * HOW DOES THIS WORK + * + * There are two stages to data reservations, one for data and one for metadata + * to handle the new extents and checksums generated by writing data. + * + * + * DATA RESERVATION + * The general flow of the data reservation is as follows + * + * -> Reserve + * We call into btrfs_reserve_data_bytes() for the user request bytes that + * they wish to write. We make this reservation and add it to + * space_info->bytes_may_use. We set EXTENT_DELALLOC on the inode io_tree + * for the range and carry on if this is buffered, or follow up trying to + * make a real allocation if we are pre-allocating or doing O_DIRECT. + * + * -> Use + * At writepages()/prealloc/O_DIRECT time we will call into + * btrfs_reserve_extent() for some part or all of this range of bytes. We + * will make the allocation and subtract space_info->bytes_may_use by the + * original requested length and increase the space_info->bytes_reserved by + * the allocated length. This distinction is important because compression + * may allocate a smaller on disk extent than we previously reserved. + * + * -> Allocation + * finish_ordered_io() will insert the new file extent item for this range, + * and then add a delayed ref update for the extent tree. Once that delayed + * ref is written the extent size is subtracted from + * space_info->bytes_reserved and added to space_info->bytes_used. + * + * Error handling + * + * -> By the reservation maker + * This is the simplest case, we haven't completed our operation and we know + * how much we reserved, we can simply call + * btrfs_free_reserved_data_space*() and it will be removed from + * space_info->bytes_may_use. + * + * -> After the reservation has been made, but before cow_file_range() + * This is specifically for the delalloc case. You must clear + * EXTENT_DELALLOC with the EXTENT_CLEAR_DATA_RESV bit, and the range will + * be subtracted from space_info->bytes_may_use. + * + * METADATA RESERVATION + * The general metadata reservation lifetimes are discussed elsewhere, this + * will just focus on how it is used for delalloc space. + * + * We keep track of two things on a per inode bases + * + * ->outstanding_extents + * This is the number of file extent items we'll need to handle all of the + * outstanding DELALLOC space we have in this inode. We limit the maximum + * size of an extent, so a large contiguous dirty area may require more than + * one outstanding_extent, which is why count_max_extents() is used to + * determine how many outstanding_extents get added. + * + * ->csum_bytes + * This is essentially how many dirty bytes we have for this inode, so we + * can calculate the number of checksum items we would have to add in order + * to checksum our outstanding data. + * + * We keep a per-inode block_rsv in order to make it easier to keep track of + * our reservation. We use btrfs_calculate_inode_block_rsv_size() to + * calculate the current theoretical maximum reservation we would need for the + * metadata for this inode. We call this and then adjust our reservation as + * necessary, either by attempting to reserve more space, or freeing up excess + * space. + * + * OUTSTANDING_EXTENTS HANDLING + * + * ->outstanding_extents is used for keeping track of how many extents we will + * need to use for this inode, and it will fluctuate depending on where you are + * in the life cycle of the dirty data. Consider the following normal case for + * a completely clean inode, with a num_bytes < our maximum allowed extent size + * + * -> reserve + * ->outstanding_extents += 1 (current value is 1) + * + * -> set_delalloc + * ->outstanding_extents += 1 (current value is 2) + * + * -> btrfs_delalloc_release_extents() + * ->outstanding_extents -= 1 (current value is 1) + * + * We must call this once we are done, as we hold our reservation for the + * duration of our operation, and then assume set_delalloc will update the + * counter appropriately. + * + * -> add ordered extent + * ->outstanding_extents += 1 (current value is 2) + * + * -> btrfs_clear_delalloc_extent + * ->outstanding_extents -= 1 (current value is 1) + * + * -> finish_ordered_io/btrfs_remove_ordered_extent + * ->outstanding_extents -= 1 (current value is 0) + * + * Each stage is responsible for their own accounting of the extent, thus + * making error handling and cleanup easier. + */ + +int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes) +{ + struct btrfs_root *root = inode->root; + struct btrfs_fs_info *fs_info = root->fs_info; + enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_DATA; + + /* Make sure bytes are sectorsize aligned */ + bytes = ALIGN(bytes, fs_info->sectorsize); + + if (btrfs_is_free_space_inode(inode)) + flush = BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE; + + return btrfs_reserve_data_bytes(fs_info, bytes, flush); +} + +int btrfs_check_data_free_space(struct btrfs_inode *inode, + struct extent_changeset **reserved, u64 start, + u64 len, bool noflush) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_DATA; + int ret; + + /* align the range */ + len = round_up(start + len, fs_info->sectorsize) - + round_down(start, fs_info->sectorsize); + start = round_down(start, fs_info->sectorsize); + + if (noflush) + flush = BTRFS_RESERVE_NO_FLUSH; + else if (btrfs_is_free_space_inode(inode)) + flush = BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE; + + ret = btrfs_reserve_data_bytes(fs_info, len, flush); + if (ret < 0) + return ret; + + /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */ + ret = btrfs_qgroup_reserve_data(inode, reserved, start, len); + if (ret < 0) { + btrfs_free_reserved_data_space_noquota(fs_info, len); + extent_changeset_free(*reserved); + *reserved = NULL; + } else { + ret = 0; + } + return ret; +} + +/* + * Called if we need to clear a data reservation for this inode + * Normally in a error case. + * + * This one will *NOT* use accurate qgroup reserved space API, just for case + * which we can't sleep and is sure it won't affect qgroup reserved space. + * Like clear_bit_hook(). + */ +void btrfs_free_reserved_data_space_noquota(struct btrfs_fs_info *fs_info, + u64 len) +{ + struct btrfs_space_info *data_sinfo; + + ASSERT(IS_ALIGNED(len, fs_info->sectorsize)); + + data_sinfo = fs_info->data_sinfo; + btrfs_space_info_free_bytes_may_use(fs_info, data_sinfo, len); +} + +/* + * Called if we need to clear a data reservation for this inode + * Normally in a error case. + * + * This one will handle the per-inode data rsv map for accurate reserved + * space framework. + */ +void btrfs_free_reserved_data_space(struct btrfs_inode *inode, + struct extent_changeset *reserved, u64 start, u64 len) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + + /* Make sure the range is aligned to sectorsize */ + len = round_up(start + len, fs_info->sectorsize) - + round_down(start, fs_info->sectorsize); + start = round_down(start, fs_info->sectorsize); + + btrfs_free_reserved_data_space_noquota(fs_info, len); + btrfs_qgroup_free_data(inode, reserved, start, len, NULL); +} + +/** + * Release any excessive reservation + * + * @inode: the inode we need to release from + * @qgroup_free: free or convert qgroup meta. Unlike normal operation, qgroup + * meta reservation needs to know if we are freeing qgroup + * reservation or just converting it into per-trans. Normally + * @qgroup_free is true for error handling, and false for normal + * release. + * + * This is the same as btrfs_block_rsv_release, except that it handles the + * tracepoint for the reservation. + */ +static void btrfs_inode_rsv_release(struct btrfs_inode *inode, bool qgroup_free) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + struct btrfs_block_rsv *block_rsv = &inode->block_rsv; + u64 released = 0; + u64 qgroup_to_release = 0; + + /* + * Since we statically set the block_rsv->size we just want to say we + * are releasing 0 bytes, and then we'll just get the reservation over + * the size free'd. + */ + released = btrfs_block_rsv_release(fs_info, block_rsv, 0, + &qgroup_to_release); + if (released > 0) + trace_btrfs_space_reservation(fs_info, "delalloc", + btrfs_ino(inode), released, 0); + if (qgroup_free) + btrfs_qgroup_free_meta_prealloc(inode->root, qgroup_to_release); + else + btrfs_qgroup_convert_reserved_meta(inode->root, + qgroup_to_release); +} + +static void btrfs_calculate_inode_block_rsv_size(struct btrfs_fs_info *fs_info, + struct btrfs_inode *inode) +{ + struct btrfs_block_rsv *block_rsv = &inode->block_rsv; + u64 reserve_size = 0; + u64 qgroup_rsv_size = 0; + u64 csum_leaves; + unsigned outstanding_extents; + + lockdep_assert_held(&inode->lock); + outstanding_extents = inode->outstanding_extents; + + /* + * Insert size for the number of outstanding extents, 1 normal size for + * updating the inode. + */ + if (outstanding_extents) { + reserve_size = btrfs_calc_insert_metadata_size(fs_info, + outstanding_extents); + reserve_size += btrfs_calc_metadata_size(fs_info, 1); + } + csum_leaves = btrfs_csum_bytes_to_leaves(fs_info, + inode->csum_bytes); + reserve_size += btrfs_calc_insert_metadata_size(fs_info, + csum_leaves); + /* + * For qgroup rsv, the calculation is very simple: + * account one nodesize for each outstanding extent + * + * This is overestimating in most cases. + */ + qgroup_rsv_size = (u64)outstanding_extents * fs_info->nodesize; + + spin_lock(&block_rsv->lock); + block_rsv->size = reserve_size; + block_rsv->qgroup_rsv_size = qgroup_rsv_size; + spin_unlock(&block_rsv->lock); +} + +static void calc_inode_reservations(struct btrfs_fs_info *fs_info, + u64 num_bytes, u64 disk_num_bytes, + u64 *meta_reserve, u64 *qgroup_reserve) +{ + u64 nr_extents = count_max_extents(fs_info, num_bytes); + u64 csum_leaves = btrfs_csum_bytes_to_leaves(fs_info, disk_num_bytes); + u64 inode_update = btrfs_calc_metadata_size(fs_info, 1); + + *meta_reserve = btrfs_calc_insert_metadata_size(fs_info, + nr_extents + csum_leaves); + + /* + * finish_ordered_io has to update the inode, so add the space required + * for an inode update. + */ + *meta_reserve += inode_update; + *qgroup_reserve = nr_extents * fs_info->nodesize; +} + +int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes, + u64 disk_num_bytes, bool noflush) +{ + struct btrfs_root *root = inode->root; + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_block_rsv *block_rsv = &inode->block_rsv; + u64 meta_reserve, qgroup_reserve; + unsigned nr_extents; + enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL; + int ret = 0; + + /* + * If we are a free space inode we need to not flush since we will be in + * the middle of a transaction commit. We also don't need the delalloc + * mutex since we won't race with anybody. We need this mostly to make + * lockdep shut its filthy mouth. + * + * If we have a transaction open (can happen if we call truncate_block + * from truncate), then we need FLUSH_LIMIT so we don't deadlock. + */ + if (noflush || btrfs_is_free_space_inode(inode)) { + flush = BTRFS_RESERVE_NO_FLUSH; + } else { + if (current->journal_info) + flush = BTRFS_RESERVE_FLUSH_LIMIT; + } + + num_bytes = ALIGN(num_bytes, fs_info->sectorsize); + disk_num_bytes = ALIGN(disk_num_bytes, fs_info->sectorsize); + + /* + * We always want to do it this way, every other way is wrong and ends + * in tears. Pre-reserving the amount we are going to add will always + * be the right way, because otherwise if we have enough parallelism we + * could end up with thousands of inodes all holding little bits of + * reservations they were able to make previously and the only way to + * reclaim that space is to ENOSPC out the operations and clear + * everything out and try again, which is bad. This way we just + * over-reserve slightly, and clean up the mess when we are done. + */ + calc_inode_reservations(fs_info, num_bytes, disk_num_bytes, + &meta_reserve, &qgroup_reserve); + ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_reserve, true, + noflush); + if (ret) + return ret; + ret = btrfs_reserve_metadata_bytes(fs_info, block_rsv, meta_reserve, flush); + if (ret) { + btrfs_qgroup_free_meta_prealloc(root, qgroup_reserve); + return ret; + } + + /* + * Now we need to update our outstanding extents and csum bytes _first_ + * and then add the reservation to the block_rsv. This keeps us from + * racing with an ordered completion or some such that would think it + * needs to free the reservation we just made. + */ + spin_lock(&inode->lock); + nr_extents = count_max_extents(fs_info, num_bytes); + btrfs_mod_outstanding_extents(inode, nr_extents); + inode->csum_bytes += disk_num_bytes; + btrfs_calculate_inode_block_rsv_size(fs_info, inode); + spin_unlock(&inode->lock); + + /* Now we can safely add our space to our block rsv */ + btrfs_block_rsv_add_bytes(block_rsv, meta_reserve, false); + trace_btrfs_space_reservation(root->fs_info, "delalloc", + btrfs_ino(inode), meta_reserve, 1); + + spin_lock(&block_rsv->lock); + block_rsv->qgroup_rsv_reserved += qgroup_reserve; + spin_unlock(&block_rsv->lock); + + return 0; +} + +/** + * Release a metadata reservation for an inode + * + * @inode: the inode to release the reservation for. + * @num_bytes: the number of bytes we are releasing. + * @qgroup_free: free qgroup reservation or convert it to per-trans reservation + * + * This will release the metadata reservation for an inode. This can be called + * once we complete IO for a given set of bytes to release their metadata + * reservations, or on error for the same reason. + */ +void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes, + bool qgroup_free) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + + num_bytes = ALIGN(num_bytes, fs_info->sectorsize); + spin_lock(&inode->lock); + inode->csum_bytes -= num_bytes; + btrfs_calculate_inode_block_rsv_size(fs_info, inode); + spin_unlock(&inode->lock); + + if (btrfs_is_testing(fs_info)) + return; + + btrfs_inode_rsv_release(inode, qgroup_free); +} + +/** + * btrfs_delalloc_release_extents - release our outstanding_extents + * @inode: the inode to balance the reservation for. + * @num_bytes: the number of bytes we originally reserved with + * + * When we reserve space we increase outstanding_extents for the extents we may + * add. Once we've set the range as delalloc or created our ordered extents we + * have outstanding_extents to track the real usage, so we use this to free our + * temporarily tracked outstanding_extents. This _must_ be used in conjunction + * with btrfs_delalloc_reserve_metadata. + */ +void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + unsigned num_extents; + + spin_lock(&inode->lock); + num_extents = count_max_extents(fs_info, num_bytes); + btrfs_mod_outstanding_extents(inode, -num_extents); + btrfs_calculate_inode_block_rsv_size(fs_info, inode); + spin_unlock(&inode->lock); + + if (btrfs_is_testing(fs_info)) + return; + + btrfs_inode_rsv_release(inode, true); +} + +/** + * btrfs_delalloc_reserve_space - reserve data and metadata space for + * delalloc + * @inode: inode we're writing to + * @start: start range we are writing to + * @len: how long the range we are writing to + * @reserved: mandatory parameter, record actually reserved qgroup ranges of + * current reservation. + * + * This will do the following things + * + * - reserve space in data space info for num bytes + * and reserve precious corresponding qgroup space + * (Done in check_data_free_space) + * + * - reserve space for metadata space, based on the number of outstanding + * extents and how much csums will be needed + * also reserve metadata space in a per root over-reserve method. + * - add to the inodes->delalloc_bytes + * - add it to the fs_info's delalloc inodes list. + * (Above 3 all done in delalloc_reserve_metadata) + * + * Return 0 for success + * Return <0 for error(-ENOSPC or -EQUOT) + */ +int btrfs_delalloc_reserve_space(struct btrfs_inode *inode, + struct extent_changeset **reserved, u64 start, u64 len) +{ + int ret; + + ret = btrfs_check_data_free_space(inode, reserved, start, len, false); + if (ret < 0) + return ret; + ret = btrfs_delalloc_reserve_metadata(inode, len, len, false); + if (ret < 0) { + btrfs_free_reserved_data_space(inode, *reserved, start, len); + extent_changeset_free(*reserved); + *reserved = NULL; + } + return ret; +} + +/** + * Release data and metadata space for delalloc + * + * @inode: inode we're releasing space for + * @reserved: list of changed/reserved ranges + * @start: start position of the space already reserved + * @len: length of the space already reserved + * @qgroup_free: should qgroup reserved-space also be freed + * + * This function will release the metadata space that was not used and will + * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes + * list if there are no delalloc bytes left. + * Also it will handle the qgroup reserved space. + */ +void btrfs_delalloc_release_space(struct btrfs_inode *inode, + struct extent_changeset *reserved, + u64 start, u64 len, bool qgroup_free) +{ + btrfs_delalloc_release_metadata(inode, len, qgroup_free); + btrfs_free_reserved_data_space(inode, reserved, start, len); +} -- cgit v1.2.3