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Diffstat (limited to 'fs/xfs/xfs_buf_item.c')
| -rw-r--r-- | fs/xfs/xfs_buf_item.c | 1050 |
1 files changed, 1050 insertions, 0 deletions
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c new file mode 100644 index 00000000..eac97ef8 --- /dev/null +++ b/fs/xfs/xfs_buf_item.c @@ -0,0 +1,1050 @@ +/* + * Copyright (c) 2000-2005 Silicon Graphics, Inc. + * All Rights Reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it would be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ +#include "xfs.h" +#include "xfs_fs.h" +#include "xfs_types.h" +#include "xfs_bit.h" +#include "xfs_log.h" +#include "xfs_inum.h" +#include "xfs_trans.h" +#include "xfs_sb.h" +#include "xfs_ag.h" +#include "xfs_mount.h" +#include "xfs_buf_item.h" +#include "xfs_trans_priv.h" +#include "xfs_error.h" +#include "xfs_trace.h" + + +kmem_zone_t *xfs_buf_item_zone; + +static inline struct xfs_buf_log_item *BUF_ITEM(struct xfs_log_item *lip) +{ + return container_of(lip, struct xfs_buf_log_item, bli_item); +} + + +#ifdef XFS_TRANS_DEBUG +/* + * This function uses an alternate strategy for tracking the bytes + * that the user requests to be logged. This can then be used + * in conjunction with the bli_orig array in the buf log item to + * catch bugs in our callers' code. + * + * We also double check the bits set in xfs_buf_item_log using a + * simple algorithm to check that every byte is accounted for. + */ +STATIC void +xfs_buf_item_log_debug( + xfs_buf_log_item_t *bip, + uint first, + uint last) +{ + uint x; + uint byte; + uint nbytes; + uint chunk_num; + uint word_num; + uint bit_num; + uint bit_set; + uint *wordp; + + ASSERT(bip->bli_logged != NULL); + byte = first; + nbytes = last - first + 1; + bfset(bip->bli_logged, first, nbytes); + for (x = 0; x < nbytes; x++) { + chunk_num = byte >> XFS_BLF_SHIFT; + word_num = chunk_num >> BIT_TO_WORD_SHIFT; + bit_num = chunk_num & (NBWORD - 1); + wordp = &(bip->bli_format.blf_data_map[word_num]); + bit_set = *wordp & (1 << bit_num); + ASSERT(bit_set); + byte++; + } +} + +/* + * This function is called when we flush something into a buffer without + * logging it. This happens for things like inodes which are logged + * separately from the buffer. + */ +void +xfs_buf_item_flush_log_debug( + xfs_buf_t *bp, + uint first, + uint last) +{ + xfs_buf_log_item_t *bip = bp->b_fspriv; + uint nbytes; + + if (bip == NULL || (bip->bli_item.li_type != XFS_LI_BUF)) + return; + + ASSERT(bip->bli_logged != NULL); + nbytes = last - first + 1; + bfset(bip->bli_logged, first, nbytes); +} + +/* + * This function is called to verify that our callers have logged + * all the bytes that they changed. + * + * It does this by comparing the original copy of the buffer stored in + * the buf log item's bli_orig array to the current copy of the buffer + * and ensuring that all bytes which mismatch are set in the bli_logged + * array of the buf log item. + */ +STATIC void +xfs_buf_item_log_check( + xfs_buf_log_item_t *bip) +{ + char *orig; + char *buffer; + int x; + xfs_buf_t *bp; + + ASSERT(bip->bli_orig != NULL); + ASSERT(bip->bli_logged != NULL); + + bp = bip->bli_buf; + ASSERT(XFS_BUF_COUNT(bp) > 0); + ASSERT(bp->b_addr != NULL); + orig = bip->bli_orig; + buffer = bp->b_addr; + for (x = 0; x < XFS_BUF_COUNT(bp); x++) { + if (orig[x] != buffer[x] && !btst(bip->bli_logged, x)) { + xfs_emerg(bp->b_mount, + "%s: bip %x buffer %x orig %x index %d", + __func__, bip, bp, orig, x); + ASSERT(0); + } + } +} +#else +#define xfs_buf_item_log_debug(x,y,z) +#define xfs_buf_item_log_check(x) +#endif + +STATIC void xfs_buf_do_callbacks(struct xfs_buf *bp); + +/* + * This returns the number of log iovecs needed to log the + * given buf log item. + * + * It calculates this as 1 iovec for the buf log format structure + * and 1 for each stretch of non-contiguous chunks to be logged. + * Contiguous chunks are logged in a single iovec. + * + * If the XFS_BLI_STALE flag has been set, then log nothing. + */ +STATIC uint +xfs_buf_item_size( + struct xfs_log_item *lip) +{ + struct xfs_buf_log_item *bip = BUF_ITEM(lip); + struct xfs_buf *bp = bip->bli_buf; + uint nvecs; + int next_bit; + int last_bit; + + ASSERT(atomic_read(&bip->bli_refcount) > 0); + if (bip->bli_flags & XFS_BLI_STALE) { + /* + * The buffer is stale, so all we need to log + * is the buf log format structure with the + * cancel flag in it. + */ + trace_xfs_buf_item_size_stale(bip); + ASSERT(bip->bli_format.blf_flags & XFS_BLF_CANCEL); + return 1; + } + + ASSERT(bip->bli_flags & XFS_BLI_LOGGED); + nvecs = 1; + last_bit = xfs_next_bit(bip->bli_format.blf_data_map, + bip->bli_format.blf_map_size, 0); + ASSERT(last_bit != -1); + nvecs++; + while (last_bit != -1) { + /* + * This takes the bit number to start looking from and + * returns the next set bit from there. It returns -1 + * if there are no more bits set or the start bit is + * beyond the end of the bitmap. + */ + next_bit = xfs_next_bit(bip->bli_format.blf_data_map, + bip->bli_format.blf_map_size, + last_bit + 1); + /* + * If we run out of bits, leave the loop, + * else if we find a new set of bits bump the number of vecs, + * else keep scanning the current set of bits. + */ + if (next_bit == -1) { + last_bit = -1; + } else if (next_bit != last_bit + 1) { + last_bit = next_bit; + nvecs++; + } else if (xfs_buf_offset(bp, next_bit * XFS_BLF_CHUNK) != + (xfs_buf_offset(bp, last_bit * XFS_BLF_CHUNK) + + XFS_BLF_CHUNK)) { + last_bit = next_bit; + nvecs++; + } else { + last_bit++; + } + } + + trace_xfs_buf_item_size(bip); + return nvecs; +} + +/* + * This is called to fill in the vector of log iovecs for the + * given log buf item. It fills the first entry with a buf log + * format structure, and the rest point to contiguous chunks + * within the buffer. + */ +STATIC void +xfs_buf_item_format( + struct xfs_log_item *lip, + struct xfs_log_iovec *vecp) +{ + struct xfs_buf_log_item *bip = BUF_ITEM(lip); + struct xfs_buf *bp = bip->bli_buf; + uint base_size; + uint nvecs; + int first_bit; + int last_bit; + int next_bit; + uint nbits; + uint buffer_offset; + + ASSERT(atomic_read(&bip->bli_refcount) > 0); + ASSERT((bip->bli_flags & XFS_BLI_LOGGED) || + (bip->bli_flags & XFS_BLI_STALE)); + + /* + * The size of the base structure is the size of the + * declared structure plus the space for the extra words + * of the bitmap. We subtract one from the map size, because + * the first element of the bitmap is accounted for in the + * size of the base structure. + */ + base_size = + (uint)(sizeof(xfs_buf_log_format_t) + + ((bip->bli_format.blf_map_size - 1) * sizeof(uint))); + vecp->i_addr = &bip->bli_format; + vecp->i_len = base_size; + vecp->i_type = XLOG_REG_TYPE_BFORMAT; + vecp++; + nvecs = 1; + + /* + * If it is an inode buffer, transfer the in-memory state to the + * format flags and clear the in-memory state. We do not transfer + * this state if the inode buffer allocation has not yet been committed + * to the log as setting the XFS_BLI_INODE_BUF flag will prevent + * correct replay of the inode allocation. + */ + if (bip->bli_flags & XFS_BLI_INODE_BUF) { + if (!((bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF) && + xfs_log_item_in_current_chkpt(lip))) + bip->bli_format.blf_flags |= XFS_BLF_INODE_BUF; + bip->bli_flags &= ~XFS_BLI_INODE_BUF; + } + + if (bip->bli_flags & XFS_BLI_STALE) { + /* + * The buffer is stale, so all we need to log + * is the buf log format structure with the + * cancel flag in it. + */ + trace_xfs_buf_item_format_stale(bip); + ASSERT(bip->bli_format.blf_flags & XFS_BLF_CANCEL); + bip->bli_format.blf_size = nvecs; + return; + } + + /* + * Fill in an iovec for each set of contiguous chunks. + */ + first_bit = xfs_next_bit(bip->bli_format.blf_data_map, + bip->bli_format.blf_map_size, 0); + ASSERT(first_bit != -1); + last_bit = first_bit; + nbits = 1; + for (;;) { + /* + * This takes the bit number to start looking from and + * returns the next set bit from there. It returns -1 + * if there are no more bits set or the start bit is + * beyond the end of the bitmap. + */ + next_bit = xfs_next_bit(bip->bli_format.blf_data_map, + bip->bli_format.blf_map_size, + (uint)last_bit + 1); + /* + * If we run out of bits fill in the last iovec and get + * out of the loop. + * Else if we start a new set of bits then fill in the + * iovec for the series we were looking at and start + * counting the bits in the new one. + * Else we're still in the same set of bits so just + * keep counting and scanning. + */ + if (next_bit == -1) { + buffer_offset = first_bit * XFS_BLF_CHUNK; + vecp->i_addr = xfs_buf_offset(bp, buffer_offset); + vecp->i_len = nbits * XFS_BLF_CHUNK; + vecp->i_type = XLOG_REG_TYPE_BCHUNK; + nvecs++; + break; + } else if (next_bit != last_bit + 1) { + buffer_offset = first_bit * XFS_BLF_CHUNK; + vecp->i_addr = xfs_buf_offset(bp, buffer_offset); + vecp->i_len = nbits * XFS_BLF_CHUNK; + vecp->i_type = XLOG_REG_TYPE_BCHUNK; + nvecs++; + vecp++; + first_bit = next_bit; + last_bit = next_bit; + nbits = 1; + } else if (xfs_buf_offset(bp, next_bit << XFS_BLF_SHIFT) != + (xfs_buf_offset(bp, last_bit << XFS_BLF_SHIFT) + + XFS_BLF_CHUNK)) { + buffer_offset = first_bit * XFS_BLF_CHUNK; + vecp->i_addr = xfs_buf_offset(bp, buffer_offset); + vecp->i_len = nbits * XFS_BLF_CHUNK; + vecp->i_type = XLOG_REG_TYPE_BCHUNK; +/* You would think we need to bump the nvecs here too, but we do not + * this number is used by recovery, and it gets confused by the boundary + * split here + * nvecs++; + */ + vecp++; + first_bit = next_bit; + last_bit = next_bit; + nbits = 1; + } else { + last_bit++; + nbits++; + } + } + bip->bli_format.blf_size = nvecs; + + /* + * Check to make sure everything is consistent. + */ + trace_xfs_buf_item_format(bip); + xfs_buf_item_log_check(bip); +} + +/* + * This is called to pin the buffer associated with the buf log item in memory + * so it cannot be written out. + * + * We also always take a reference to the buffer log item here so that the bli + * is held while the item is pinned in memory. This means that we can + * unconditionally drop the reference count a transaction holds when the + * transaction is completed. + */ +STATIC void +xfs_buf_item_pin( + struct xfs_log_item *lip) +{ + struct xfs_buf_log_item *bip = BUF_ITEM(lip); + + ASSERT(atomic_read(&bip->bli_refcount) > 0); + ASSERT((bip->bli_flags & XFS_BLI_LOGGED) || + (bip->bli_flags & XFS_BLI_STALE)); + + trace_xfs_buf_item_pin(bip); + + atomic_inc(&bip->bli_refcount); + atomic_inc(&bip->bli_buf->b_pin_count); +} + +/* + * This is called to unpin the buffer associated with the buf log + * item which was previously pinned with a call to xfs_buf_item_pin(). + * + * Also drop the reference to the buf item for the current transaction. + * If the XFS_BLI_STALE flag is set and we are the last reference, + * then free up the buf log item and unlock the buffer. + * + * If the remove flag is set we are called from uncommit in the + * forced-shutdown path. If that is true and the reference count on + * the log item is going to drop to zero we need to free the item's + * descriptor in the transaction. + */ +STATIC void +xfs_buf_item_unpin( + struct xfs_log_item *lip, + int remove) +{ + struct xfs_buf_log_item *bip = BUF_ITEM(lip); + xfs_buf_t *bp = bip->bli_buf; + struct xfs_ail *ailp = lip->li_ailp; + int stale = bip->bli_flags & XFS_BLI_STALE; + int freed; + + ASSERT(bp->b_fspriv == bip); + ASSERT(atomic_read(&bip->bli_refcount) > 0); + + trace_xfs_buf_item_unpin(bip); + + freed = atomic_dec_and_test(&bip->bli_refcount); + + if (atomic_dec_and_test(&bp->b_pin_count)) + wake_up_all(&bp->b_waiters); + + if (freed && stale) { + ASSERT(bip->bli_flags & XFS_BLI_STALE); + ASSERT(xfs_buf_islocked(bp)); + ASSERT(!(XFS_BUF_ISDELAYWRITE(bp))); + ASSERT(XFS_BUF_ISSTALE(bp)); + ASSERT(bip->bli_format.blf_flags & XFS_BLF_CANCEL); + + trace_xfs_buf_item_unpin_stale(bip); + + if (remove) { + /* + * If we are in a transaction context, we have to + * remove the log item from the transaction as we are + * about to release our reference to the buffer. If we + * don't, the unlock that occurs later in + * xfs_trans_uncommit() will try to reference the + * buffer which we no longer have a hold on. + */ + if (lip->li_desc) + xfs_trans_del_item(lip); + + /* + * Since the transaction no longer refers to the buffer, + * the buffer should no longer refer to the transaction. + */ + bp->b_transp = NULL; + } + + /* + * If we get called here because of an IO error, we may + * or may not have the item on the AIL. xfs_trans_ail_delete() + * will take care of that situation. + * xfs_trans_ail_delete() drops the AIL lock. + */ + if (bip->bli_flags & XFS_BLI_STALE_INODE) { + xfs_buf_do_callbacks(bp); + bp->b_fspriv = NULL; + bp->b_iodone = NULL; + } else { + spin_lock(&ailp->xa_lock); + xfs_trans_ail_delete(ailp, (xfs_log_item_t *)bip); + xfs_buf_item_relse(bp); + ASSERT(bp->b_fspriv == NULL); + } + xfs_buf_relse(bp); + } +} + +/* + * This is called to attempt to lock the buffer associated with this + * buf log item. Don't sleep on the buffer lock. If we can't get + * the lock right away, return 0. If we can get the lock, take a + * reference to the buffer. If this is a delayed write buffer that + * needs AIL help to be written back, invoke the pushbuf routine + * rather than the normal success path. + */ +STATIC uint +xfs_buf_item_trylock( + struct xfs_log_item *lip) +{ + struct xfs_buf_log_item *bip = BUF_ITEM(lip); + struct xfs_buf *bp = bip->bli_buf; + + if (xfs_buf_ispinned(bp)) + return XFS_ITEM_PINNED; + if (!xfs_buf_trylock(bp)) + return XFS_ITEM_LOCKED; + + /* take a reference to the buffer. */ + xfs_buf_hold(bp); + + ASSERT(!(bip->bli_flags & XFS_BLI_STALE)); + trace_xfs_buf_item_trylock(bip); + if (XFS_BUF_ISDELAYWRITE(bp)) + return XFS_ITEM_PUSHBUF; + return XFS_ITEM_SUCCESS; +} + +/* + * Release the buffer associated with the buf log item. If there is no dirty + * logged data associated with the buffer recorded in the buf log item, then + * free the buf log item and remove the reference to it in the buffer. + * + * This call ignores the recursion count. It is only called when the buffer + * should REALLY be unlocked, regardless of the recursion count. + * + * We unconditionally drop the transaction's reference to the log item. If the + * item was logged, then another reference was taken when it was pinned, so we + * can safely drop the transaction reference now. This also allows us to avoid + * potential races with the unpin code freeing the bli by not referencing the + * bli after we've dropped the reference count. + * + * If the XFS_BLI_HOLD flag is set in the buf log item, then free the log item + * if necessary but do not unlock the buffer. This is for support of + * xfs_trans_bhold(). Make sure the XFS_BLI_HOLD field is cleared if we don't + * free the item. + */ +STATIC void +xfs_buf_item_unlock( + struct xfs_log_item *lip) +{ + struct xfs_buf_log_item *bip = BUF_ITEM(lip); + struct xfs_buf *bp = bip->bli_buf; + int aborted; + uint hold; + + /* Clear the buffer's association with this transaction. */ + bp->b_transp = NULL; + + /* + * If this is a transaction abort, don't return early. Instead, allow + * the brelse to happen. Normally it would be done for stale + * (cancelled) buffers at unpin time, but we'll never go through the + * pin/unpin cycle if we abort inside commit. + */ + aborted = (lip->li_flags & XFS_LI_ABORTED) != 0; + + /* + * Before possibly freeing the buf item, determine if we should + * release the buffer at the end of this routine. + */ + hold = bip->bli_flags & XFS_BLI_HOLD; + + /* Clear the per transaction state. */ + bip->bli_flags &= ~(XFS_BLI_LOGGED | XFS_BLI_HOLD); + + /* + * If the buf item is marked stale, then don't do anything. We'll + * unlock the buffer and free the buf item when the buffer is unpinned + * for the last time. + */ + if (bip->bli_flags & XFS_BLI_STALE) { + trace_xfs_buf_item_unlock_stale(bip); + ASSERT(bip->bli_format.blf_flags & XFS_BLF_CANCEL); + if (!aborted) { + atomic_dec(&bip->bli_refcount); + return; + } + } + + trace_xfs_buf_item_unlock(bip); + + /* + * If the buf item isn't tracking any data, free it, otherwise drop the + * reference we hold to it. + */ + if (xfs_bitmap_empty(bip->bli_format.blf_data_map, + bip->bli_format.blf_map_size)) + xfs_buf_item_relse(bp); + else + atomic_dec(&bip->bli_refcount); + + if (!hold) + xfs_buf_relse(bp); +} + +/* + * This is called to find out where the oldest active copy of the + * buf log item in the on disk log resides now that the last log + * write of it completed at the given lsn. + * We always re-log all the dirty data in a buffer, so usually the + * latest copy in the on disk log is the only one that matters. For + * those cases we simply return the given lsn. + * + * The one exception to this is for buffers full of newly allocated + * inodes. These buffers are only relogged with the XFS_BLI_INODE_BUF + * flag set, indicating that only the di_next_unlinked fields from the + * inodes in the buffers will be replayed during recovery. If the + * original newly allocated inode images have not yet been flushed + * when the buffer is so relogged, then we need to make sure that we + * keep the old images in the 'active' portion of the log. We do this + * by returning the original lsn of that transaction here rather than + * the current one. + */ +STATIC xfs_lsn_t +xfs_buf_item_committed( + struct xfs_log_item *lip, + xfs_lsn_t lsn) +{ + struct xfs_buf_log_item *bip = BUF_ITEM(lip); + + trace_xfs_buf_item_committed(bip); + + if ((bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF) && lip->li_lsn != 0) + return lip->li_lsn; + return lsn; +} + +/* + * The buffer is locked, but is not a delayed write buffer. This happens + * if we race with IO completion and hence we don't want to try to write it + * again. Just release the buffer. + */ +STATIC void +xfs_buf_item_push( + struct xfs_log_item *lip) +{ + struct xfs_buf_log_item *bip = BUF_ITEM(lip); + struct xfs_buf *bp = bip->bli_buf; + + ASSERT(!(bip->bli_flags & XFS_BLI_STALE)); + ASSERT(!XFS_BUF_ISDELAYWRITE(bp)); + + trace_xfs_buf_item_push(bip); + + xfs_buf_relse(bp); +} + +/* + * The buffer is locked and is a delayed write buffer. Promote the buffer + * in the delayed write queue as the caller knows that they must invoke + * the xfsbufd to get this buffer written. We have to unlock the buffer + * to allow the xfsbufd to write it, too. + */ +STATIC bool +xfs_buf_item_pushbuf( + struct xfs_log_item *lip) +{ + struct xfs_buf_log_item *bip = BUF_ITEM(lip); + struct xfs_buf *bp = bip->bli_buf; + + ASSERT(!(bip->bli_flags & XFS_BLI_STALE)); + ASSERT(XFS_BUF_ISDELAYWRITE(bp)); + + trace_xfs_buf_item_pushbuf(bip); + + xfs_buf_delwri_promote(bp); + xfs_buf_relse(bp); + return true; +} + +STATIC void +xfs_buf_item_committing( + struct xfs_log_item *lip, + xfs_lsn_t commit_lsn) +{ +} + +/* + * This is the ops vector shared by all buf log items. + */ +static const struct xfs_item_ops xfs_buf_item_ops = { + .iop_size = xfs_buf_item_size, + .iop_format = xfs_buf_item_format, + .iop_pin = xfs_buf_item_pin, + .iop_unpin = xfs_buf_item_unpin, + .iop_trylock = xfs_buf_item_trylock, + .iop_unlock = xfs_buf_item_unlock, + .iop_committed = xfs_buf_item_committed, + .iop_push = xfs_buf_item_push, + .iop_pushbuf = xfs_buf_item_pushbuf, + .iop_committing = xfs_buf_item_committing +}; + + +/* + * Allocate a new buf log item to go with the given buffer. + * Set the buffer's b_fsprivate field to point to the new + * buf log item. If there are other item's attached to the + * buffer (see xfs_buf_attach_iodone() below), then put the + * buf log item at the front. + */ +void +xfs_buf_item_init( + xfs_buf_t *bp, + xfs_mount_t *mp) +{ + xfs_log_item_t *lip = bp->b_fspriv; + xfs_buf_log_item_t *bip; + int chunks; + int map_size; + + /* + * Check to see if there is already a buf log item for + * this buffer. If there is, it is guaranteed to be + * the first. If we do already have one, there is + * nothing to do here so return. + */ + ASSERT(bp->b_target->bt_mount == mp); + if (lip != NULL && lip->li_type == XFS_LI_BUF) + return; + + /* + * chunks is the number of XFS_BLF_CHUNK size pieces + * the buffer can be divided into. Make sure not to + * truncate any pieces. map_size is the size of the + * bitmap needed to describe the chunks of the buffer. + */ + chunks = (int)((XFS_BUF_COUNT(bp) + (XFS_BLF_CHUNK - 1)) >> XFS_BLF_SHIFT); + map_size = (int)((chunks + NBWORD) >> BIT_TO_WORD_SHIFT); + + bip = (xfs_buf_log_item_t*)kmem_zone_zalloc(xfs_buf_item_zone, + KM_SLEEP); + xfs_log_item_init(mp, &bip->bli_item, XFS_LI_BUF, &xfs_buf_item_ops); + bip->bli_buf = bp; + xfs_buf_hold(bp); + bip->bli_format.blf_type = XFS_LI_BUF; + bip->bli_format.blf_blkno = (__int64_t)XFS_BUF_ADDR(bp); + bip->bli_format.blf_len = (ushort)BTOBB(XFS_BUF_COUNT(bp)); + bip->bli_format.blf_map_size = map_size; + +#ifdef XFS_TRANS_DEBUG + /* + * Allocate the arrays for tracking what needs to be logged + * and what our callers request to be logged. bli_orig + * holds a copy of the original, clean buffer for comparison + * against, and bli_logged keeps a 1 bit flag per byte in + * the buffer to indicate which bytes the callers have asked + * to have logged. + */ + bip->bli_orig = (char *)kmem_alloc(XFS_BUF_COUNT(bp), KM_SLEEP); + memcpy(bip->bli_orig, bp->b_addr, XFS_BUF_COUNT(bp)); + bip->bli_logged = (char *)kmem_zalloc(XFS_BUF_COUNT(bp) / NBBY, KM_SLEEP); +#endif + + /* + * Put the buf item into the list of items attached to the + * buffer at the front. + */ + if (bp->b_fspriv) + bip->bli_item.li_bio_list = bp->b_fspriv; + bp->b_fspriv = bip; +} + + +/* + * Mark bytes first through last inclusive as dirty in the buf + * item's bitmap. + */ +void +xfs_buf_item_log( + xfs_buf_log_item_t *bip, + uint first, + uint last) +{ + uint first_bit; + uint last_bit; + uint bits_to_set; + uint bits_set; + uint word_num; + uint *wordp; + uint bit; + uint end_bit; + uint mask; + + /* + * Mark the item as having some dirty data for + * quick reference in xfs_buf_item_dirty. + */ + bip->bli_flags |= XFS_BLI_DIRTY; + + /* + * Convert byte offsets to bit numbers. + */ + first_bit = first >> XFS_BLF_SHIFT; + last_bit = last >> XFS_BLF_SHIFT; + + /* + * Calculate the total number of bits to be set. + */ + bits_to_set = last_bit - first_bit + 1; + + /* + * Get a pointer to the first word in the bitmap + * to set a bit in. + */ + word_num = first_bit >> BIT_TO_WORD_SHIFT; + wordp = &(bip->bli_format.blf_data_map[word_num]); + + /* + * Calculate the starting bit in the first word. + */ + bit = first_bit & (uint)(NBWORD - 1); + + /* + * First set any bits in the first word of our range. + * If it starts at bit 0 of the word, it will be + * set below rather than here. That is what the variable + * bit tells us. The variable bits_set tracks the number + * of bits that have been set so far. End_bit is the number + * of the last bit to be set in this word plus one. + */ + if (bit) { + end_bit = MIN(bit + bits_to_set, (uint)NBWORD); + mask = ((1 << (end_bit - bit)) - 1) << bit; + *wordp |= mask; + wordp++; + bits_set = end_bit - bit; + } else { + bits_set = 0; + } + + /* + * Now set bits a whole word at a time that are between + * first_bit and last_bit. + */ + while ((bits_to_set - bits_set) >= NBWORD) { + *wordp |= 0xffffffff; + bits_set += NBWORD; + wordp++; + } + + /* + * Finally, set any bits left to be set in one last partial word. + */ + end_bit = bits_to_set - bits_set; + if (end_bit) { + mask = (1 << end_bit) - 1; + *wordp |= mask; + } + + xfs_buf_item_log_debug(bip, first, last); +} + + +/* + * Return 1 if the buffer has some data that has been logged (at any + * point, not just the current transaction) and 0 if not. + */ +uint +xfs_buf_item_dirty( + xfs_buf_log_item_t *bip) +{ + return (bip->bli_flags & XFS_BLI_DIRTY); +} + +STATIC void +xfs_buf_item_free( + xfs_buf_log_item_t *bip) +{ +#ifdef XFS_TRANS_DEBUG + kmem_free(bip->bli_orig); + kmem_free(bip->bli_logged); +#endif /* XFS_TRANS_DEBUG */ + + kmem_zone_free(xfs_buf_item_zone, bip); +} + +/* + * This is called when the buf log item is no longer needed. It should + * free the buf log item associated with the given buffer and clear + * the buffer's pointer to the buf log item. If there are no more + * items in the list, clear the b_iodone field of the buffer (see + * xfs_buf_attach_iodone() below). + */ +void +xfs_buf_item_relse( + xfs_buf_t *bp) +{ + xfs_buf_log_item_t *bip; + + trace_xfs_buf_item_relse(bp, _RET_IP_); + + bip = bp->b_fspriv; + bp->b_fspriv = bip->bli_item.li_bio_list; + if (bp->b_fspriv == NULL) + bp->b_iodone = NULL; + + xfs_buf_rele(bp); + xfs_buf_item_free(bip); +} + + +/* + * Add the given log item with its callback to the list of callbacks + * to be called when the buffer's I/O completes. If it is not set + * already, set the buffer's b_iodone() routine to be + * xfs_buf_iodone_callbacks() and link the log item into the list of + * items rooted at b_fsprivate. Items are always added as the second + * entry in the list if there is a first, because the buf item code + * assumes that the buf log item is first. + */ +void +xfs_buf_attach_iodone( + xfs_buf_t *bp, + void (*cb)(xfs_buf_t *, xfs_log_item_t *), + xfs_log_item_t *lip) +{ + xfs_log_item_t *head_lip; + + ASSERT(xfs_buf_islocked(bp)); + + lip->li_cb = cb; + head_lip = bp->b_fspriv; + if (head_lip) { + lip->li_bio_list = head_lip->li_bio_list; + head_lip->li_bio_list = lip; + } else { + bp->b_fspriv = lip; + } + + ASSERT(bp->b_iodone == NULL || + bp->b_iodone == xfs_buf_iodone_callbacks); + bp->b_iodone = xfs_buf_iodone_callbacks; +} + +/* + * We can have many callbacks on a buffer. Running the callbacks individually + * can cause a lot of contention on the AIL lock, so we allow for a single + * callback to be able to scan the remaining lip->li_bio_list for other items + * of the same type and callback to be processed in the first call. + * + * As a result, the loop walking the callback list below will also modify the + * list. it removes the first item from the list and then runs the callback. + * The loop then restarts from the new head of the list. This allows the + * callback to scan and modify the list attached to the buffer and we don't + * have to care about maintaining a next item pointer. + */ +STATIC void +xfs_buf_do_callbacks( + struct xfs_buf *bp) +{ + struct xfs_log_item *lip; + + while ((lip = bp->b_fspriv) != NULL) { + bp->b_fspriv = lip->li_bio_list; + ASSERT(lip->li_cb != NULL); + /* + * Clear the next pointer so we don't have any + * confusion if the item is added to another buf. + * Don't touch the log item after calling its + * callback, because it could have freed itself. + */ + lip->li_bio_list = NULL; + lip->li_cb(bp, lip); + } +} + +/* + * This is the iodone() function for buffers which have had callbacks + * attached to them by xfs_buf_attach_iodone(). It should remove each + * log item from the buffer's list and call the callback of each in turn. + * When done, the buffer's fsprivate field is set to NULL and the buffer + * is unlocked with a call to iodone(). + */ +void +xfs_buf_iodone_callbacks( + struct xfs_buf *bp) +{ + struct xfs_log_item *lip = bp->b_fspriv; + struct xfs_mount *mp = lip->li_mountp; + static ulong lasttime; + static xfs_buftarg_t *lasttarg; + + if (likely(!xfs_buf_geterror(bp))) + goto do_callbacks; + + /* + * If we've already decided to shutdown the filesystem because of + * I/O errors, there's no point in giving this a retry. + */ + if (XFS_FORCED_SHUTDOWN(mp)) { + xfs_buf_stale(bp); + XFS_BUF_DONE(bp); + trace_xfs_buf_item_iodone(bp, _RET_IP_); + goto do_callbacks; + } + + if (bp->b_target != lasttarg || + time_after(jiffies, (lasttime + 5*HZ))) { + lasttime = jiffies; + xfs_buf_ioerror_alert(bp, __func__); + } + lasttarg = bp->b_target; + + /* + * If the write was asynchronous then no one will be looking for the + * error. Clear the error state and write the buffer out again. + * + * During sync or umount we'll write all pending buffers again + * synchronous, which will catch these errors if they keep hanging + * around. + */ + if (XFS_BUF_ISASYNC(bp)) { + xfs_buf_ioerror(bp, 0); /* errno of 0 unsets the flag */ + + if (!XFS_BUF_ISSTALE(bp)) { + xfs_buf_delwri_queue(bp); + XFS_BUF_DONE(bp); + } + ASSERT(bp->b_iodone != NULL); + trace_xfs_buf_item_iodone_async(bp, _RET_IP_); + xfs_buf_relse(bp); + return; + } + + /* + * If the write of the buffer was synchronous, we want to make + * sure to return the error to the caller of xfs_bwrite(). + */ + xfs_buf_stale(bp); + XFS_BUF_DONE(bp); + + trace_xfs_buf_error_relse(bp, _RET_IP_); + +do_callbacks: + xfs_buf_do_callbacks(bp); + bp->b_fspriv = NULL; + bp->b_iodone = NULL; + xfs_buf_ioend(bp, 0); +} + +/* + * This is the iodone() function for buffers which have been + * logged. It is called when they are eventually flushed out. + * It should remove the buf item from the AIL, and free the buf item. + * It is called by xfs_buf_iodone_callbacks() above which will take + * care of cleaning up the buffer itself. + */ +void +xfs_buf_iodone( + struct xfs_buf *bp, + struct xfs_log_item *lip) +{ + struct xfs_ail *ailp = lip->li_ailp; + + ASSERT(BUF_ITEM(lip)->bli_buf == bp); + + xfs_buf_rele(bp); + + /* + * If we are forcibly shutting down, this may well be + * off the AIL already. That's because we simulate the + * log-committed callbacks to unpin these buffers. Or we may never + * have put this item on AIL because of the transaction was + * aborted forcibly. xfs_trans_ail_delete() takes care of these. + * + * Either way, AIL is useless if we're forcing a shutdown. + */ + spin_lock(&ailp->xa_lock); + xfs_trans_ail_delete(ailp, lip); + xfs_buf_item_free(BUF_ITEM(lip)); +} |