[PATCH RESEND 2/10] xfs: Add support FALLOC_FL_COLLAPSE_RANGE for fallocate

From: Namjae Jeon
Date: Sun Feb 02 2014 - 00:44:36 EST


From: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>

Add support FALLOC_FL_COLLAPSE_RANGE for fallocate.

Signed-off-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
Signed-off-by: Ashish Sangwan <a.sangwan@xxxxxxxxxxx>
---
fs/xfs/xfs_bmap.c | 195 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_bmap.h | 5 ++
fs/xfs/xfs_bmap_util.c | 99 ++++++++++++++++++++++++
fs/xfs/xfs_bmap_util.h | 2 +
fs/xfs/xfs_file.c | 19 ++++-
fs/xfs/xfs_trace.h | 1 +
6 files changed, 319 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 3ef11b2..aba3fc9 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -5358,3 +5358,198 @@ error0:
}
return error;
}
+
+/*
+ * Shift extent records to the left to cover a hole.
+ *
+ * The maximum number of extents to be shifted in a single operation
+ * is @num_exts, and @current_ext keeps track of the current extent
+ * index we have shifted. @offset_shift_fsb is the length by which each
+ * extent is shifted. If there is no hole to shift the extents
+ * into, this will be considered invalid operation and we abort immediately.
+ */
+int
+xfs_bmap_shift_extents(
+ struct xfs_trans *tp,
+ struct xfs_inode *ip,
+ int *done,
+ xfs_fileoff_t start_fsb,
+ xfs_fileoff_t offset_shift_fsb,
+ xfs_extnum_t *current_ext,
+ xfs_fsblock_t *firstblock,
+ struct xfs_bmap_free *flist,
+ int num_exts)
+{
+ struct xfs_btree_cur *cur;
+ struct xfs_bmbt_rec_host *gotp;
+ struct xfs_bmbt_irec got;
+ struct xfs_bmbt_irec left;
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_ifork *ifp;
+ xfs_extnum_t nexts = 0;
+ xfs_fileoff_t startoff;
+ int error = 0;
+ int i;
+ int whichfork = XFS_DATA_FORK;
+ int logflags;
+ xfs_filblks_t blockcount = 0;
+
+ if (unlikely(XFS_TEST_ERROR(
+ (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&
+ XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE),
+ mp, XFS_ERRTAG_BMAPIFORMAT, XFS_RANDOM_BMAPIFORMAT))) {
+ XFS_ERROR_REPORT("xfs_bmap_shift_extents",
+ XFS_ERRLEVEL_LOW, mp);
+ return XFS_ERROR(EFSCORRUPTED);
+ }
+
+ if (XFS_FORCED_SHUTDOWN(mp))
+ return XFS_ERROR(EIO);
+
+ ASSERT(current_ext != NULL);
+
+ ifp = XFS_IFORK_PTR(ip, whichfork);
+
+ if (!(ifp->if_flags & XFS_IFEXTENTS)) {
+ /* Read in all the extents */
+ error = xfs_iread_extents(tp, ip, whichfork);
+ if (error)
+ return error;
+ }
+
+ /*
+ * If *current_ext is 0, we would need to lookup the extent
+ * from where we would start shifting and store it in gotp.
+ */
+ if (!*current_ext) {
+ gotp = xfs_iext_bno_to_ext(ifp, start_fsb, current_ext);
+ /*
+ * gotp can be null in 2 cases: 1) if there are no extents
+ * or 2) start_fsb lies in a hole beyond which there are
+ * no extents. Either way, we are done.
+ */
+ if (!gotp) {
+ *done = 1;
+ return 0;
+ }
+ }
+
+ /* We are going to change core inode */
+ logflags = XFS_ILOG_CORE;
+
+ if (ifp->if_flags & XFS_IFBROOT) {
+ cur = xfs_bmbt_init_cursor(mp, tp, ip, whichfork);
+ cur->bc_private.b.firstblock = *firstblock;
+ cur->bc_private.b.flist = flist;
+ cur->bc_private.b.flags = 0;
+ } else {
+ cur = NULL;
+ logflags |= XFS_ILOG_DEXT;
+ }
+
+ while (nexts++ < num_exts &&
+ *current_ext < XFS_IFORK_NEXTENTS(ip, whichfork)) {
+
+ gotp = xfs_iext_get_ext(ifp, *current_ext);
+ xfs_bmbt_get_all(gotp, &got);
+ startoff = got.br_startoff - offset_shift_fsb;
+
+ /*
+ * Before shifting extent into hole, make sure that the hole
+ * is large enough to accomodate the shift.
+ */
+ if (*current_ext) {
+ xfs_bmbt_get_all(xfs_iext_get_ext(ifp,
+ *current_ext - 1), &left);
+
+ if (startoff < left.br_startoff + left.br_blockcount)
+ error = XFS_ERROR(EINVAL);
+
+ } else if (startoff > xfs_bmbt_get_startoff(gotp)) {
+ /* Hole is at the start but not large enough */
+ error = XFS_ERROR(EINVAL);
+ }
+
+ if (error)
+ goto del_cursor;
+
+ if (cur) {
+ error = xfs_bmbt_lookup_eq(cur,
+ got.br_startoff,
+ got.br_startblock,
+ got.br_blockcount,
+ &i);
+ if (error)
+ goto del_cursor;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor);
+ }
+
+ /* Check if we can merge 2 adjacent extents */
+ if (*current_ext &&
+ left.br_startoff + left.br_blockcount == startoff &&
+ left.br_startblock + left.br_blockcount ==
+ got.br_startblock &&
+ left.br_state == got.br_state &&
+ left.br_blockcount + got.br_blockcount <= MAXEXTLEN) {
+ blockcount = left.br_blockcount +
+ xfs_bmbt_get_blockcount(gotp);
+ xfs_iext_remove(ip, *current_ext, 1, 0);
+ if (cur) {
+ error = xfs_btree_delete(cur, &i);
+ if (error)
+ goto del_cursor;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor);
+ }
+ XFS_IFORK_NEXT_SET(ip, whichfork,
+ XFS_IFORK_NEXTENTS(ip, whichfork) - 1);
+ gotp = xfs_iext_get_ext(ifp, --*current_ext);
+ xfs_bmbt_get_all(gotp, &got);
+
+ /* Make cursor point to the extent we will update */
+ if (cur) {
+ error = xfs_bmbt_lookup_eq(cur,
+ got.br_startoff,
+ got.br_startblock,
+ got.br_blockcount,
+ &i);
+ if (error)
+ goto del_cursor;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, del_cursor);
+ }
+
+ xfs_bmbt_set_blockcount(gotp, blockcount);
+ got.br_blockcount = blockcount;
+ goto bmbt_update;
+ }
+
+ /* We have to update the startoff */
+ xfs_bmbt_set_startoff(gotp, startoff);
+ got.br_startoff = startoff;
+
+bmbt_update:
+ if (cur) {
+ error = xfs_bmbt_update(cur,
+ got.br_startoff,
+ got.br_startblock,
+ got.br_blockcount,
+ got.br_state);
+ if (error)
+ goto del_cursor;
+ }
+
+ (*current_ext)++;
+ }
+
+ /* Check if we are done */
+ if (*current_ext == XFS_IFORK_NEXTENTS(ip, whichfork))
+ *done = 1;
+
+del_cursor:
+ if (cur)
+ xfs_btree_del_cursor(cur,
+ error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
+
+ xfs_trans_log_inode(tp, ip, logflags);
+
+ return error;
+}
diff --git a/fs/xfs/xfs_bmap.h b/fs/xfs/xfs_bmap.h
index 33b41f3..7bfe67c 100644
--- a/fs/xfs/xfs_bmap.h
+++ b/fs/xfs/xfs_bmap.h
@@ -169,5 +169,10 @@ int xfs_bunmapi(struct xfs_trans *tp, struct xfs_inode *ip,
int xfs_check_nostate_extents(struct xfs_ifork *ifp, xfs_extnum_t idx,
xfs_extnum_t num);
uint xfs_default_attroffset(struct xfs_inode *ip);
+int xfs_bmap_shift_extents(struct xfs_trans *tp, struct xfs_inode *ip,
+ int *done, xfs_fileoff_t start_fsb,
+ xfs_fileoff_t offset_shift_fsb, xfs_extnum_t *current_ext,
+ xfs_fsblock_t *firstblock, struct xfs_bmap_free *flist,
+ int num_exts);

#endif /* __XFS_BMAP_H__ */
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 5887e41..7b62f5d 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1446,6 +1446,105 @@ out:
}

/*
+ * xfs_collapse_file_space()
+ * This routine frees disk space and shift extent for the given file.
+ *
+ * RETURNS:
+ * 0 on success
+ * errno on error
+ *
+ */
+int
+xfs_collapse_file_space(
+ struct xfs_inode *ip,
+ xfs_off_t offset,
+ xfs_off_t len)
+{
+ int done = 0;
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_trans *tp;
+ int error;
+ xfs_extnum_t current_ext = 0;
+ struct xfs_bmap_free free_list;
+ xfs_fsblock_t first_block;
+ int committed;
+ xfs_fileoff_t start_fsb;
+ xfs_fileoff_t shift_fsb;
+
+ ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
+
+ trace_xfs_collapse_file_space(ip);
+
+ start_fsb = XFS_B_TO_FSB(mp, offset + len);
+ shift_fsb = XFS_B_TO_FSB(mp, len);
+
+ /*
+ * The first thing we do is to free data blocks in the specified range
+ * by calling xfs_free_file_space(). It would also sync dirty data
+ * and invalidate page cache over the region on which collapse range
+ * is working.
+ */
+
+ error = xfs_free_file_space(ip, offset, len);
+ if (error)
+ return error;
+
+ while (!error && !done) {
+ tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
+ tp->t_flags |= XFS_TRANS_RESERVE;
+ /*
+ * We would need to reserve permanent block for transaction.
+ * This will come into picture when after shifting extent into
+ * hole we found that adjacent extents can be merged which
+ * may lead to freeing of a block during record update.
+ */
+ error = xfs_trans_reserve(tp, &M_RES(mp)->tr_write,
+ XFS_DIOSTRAT_SPACE_RES(mp, 0), 0);
+ if (error) {
+ ASSERT(error == ENOSPC || XFS_FORCED_SHUTDOWN(mp));
+ xfs_trans_cancel(tp, 0);
+ break;
+ }
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ error = xfs_trans_reserve_quota(tp, mp, ip->i_udquot,
+ ip->i_gdquot, ip->i_pdquot,
+ XFS_DIOSTRAT_SPACE_RES(mp, 0), 0,
+ XFS_QMOPT_RES_REGBLKS);
+ if (error)
+ goto out;
+
+ xfs_trans_ijoin(tp, ip, 0);
+
+ xfs_bmap_init(&free_list, &first_block);
+
+ /*
+ * We are using the write transaction in which max 2 bmbt
+ * updates are allowed
+ */
+ error = xfs_bmap_shift_extents(tp, ip, &done, start_fsb,
+ shift_fsb, &current_ext,
+ &first_block, &free_list, 2);
+ if (error)
+ goto out;
+
+ error = xfs_bmap_finish(&tp, &free_list, &committed);
+ if (error)
+ goto out;
+
+ error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ }
+
+ return error;
+
+out:
+ xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ return error;
+}
+
+/*
* We need to check that the format of the data fork in the temporary inode is
* valid for the target inode before doing the swap. This is not a problem with
* attr1 because of the fixed fork offset, but attr2 has a dynamically sized
diff --git a/fs/xfs/xfs_bmap_util.h b/fs/xfs/xfs_bmap_util.h
index 900747b..935ed2b 100644
--- a/fs/xfs/xfs_bmap_util.h
+++ b/fs/xfs/xfs_bmap_util.h
@@ -99,6 +99,8 @@ int xfs_free_file_space(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t len);
int xfs_zero_file_space(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t len);
+int xfs_collapse_file_space(struct xfs_inode *, xfs_off_t offset,
+ xfs_off_t len);

/* EOF block manipulation functions */
bool xfs_can_free_eofblocks(struct xfs_inode *ip, bool force);
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 52c91e1..accb25b 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -820,7 +820,8 @@ xfs_file_fallocate(

if (!S_ISREG(inode->i_mode))
return -EINVAL;
- if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+ if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
+ FALLOC_FL_COLLAPSE_RANGE))
return -EOPNOTSUPP;

xfs_ilock(ip, XFS_IOLOCK_EXCL);
@@ -828,6 +829,20 @@ xfs_file_fallocate(
error = xfs_free_file_space(ip, offset, len);
if (error)
goto out_unlock;
+ } else if (mode & FALLOC_FL_COLLAPSE_RANGE) {
+ unsigned blksize_mask = (1 << inode->i_blkbits) - 1;
+
+ if (offset & blksize_mask || len & blksize_mask) {
+ error = -EINVAL;
+ goto out_unlock;
+ }
+
+ ASSERT(offset + len < i_size_read(inode));
+ new_size = i_size_read(inode) - len;
+
+ error = xfs_collapse_file_space(ip, offset, len);
+ if (error)
+ goto out_unlock;
} else {
if (!(mode & FALLOC_FL_KEEP_SIZE) &&
offset + len > i_size_read(inode)) {
@@ -856,7 +871,7 @@ xfs_file_fallocate(
if (ip->i_d.di_mode & S_IXGRP)
ip->i_d.di_mode &= ~S_ISGID;

- if (!(mode & FALLOC_FL_PUNCH_HOLE))
+ if (!(mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_COLLAPSE_RANGE)))
ip->i_d.di_flags |= XFS_DIFLAG_PREALLOC;

xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 425dfa4..a4ae41c 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -603,6 +603,7 @@ DEFINE_INODE_EVENT(xfs_readlink);
DEFINE_INODE_EVENT(xfs_inactive_symlink);
DEFINE_INODE_EVENT(xfs_alloc_file_space);
DEFINE_INODE_EVENT(xfs_free_file_space);
+DEFINE_INODE_EVENT(xfs_collapse_file_space);
DEFINE_INODE_EVENT(xfs_readdir);
#ifdef CONFIG_XFS_POSIX_ACL
DEFINE_INODE_EVENT(xfs_get_acl);
--
1.7.9.5

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