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Commit 20f7e9f3 authored by Dave Chinner's avatar Dave Chinner Committed by Ben Myers
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xfs: factor dir2 block read operations 

In preparation for verifying dir2 block format buffers, factor
the read operations out of the block operations (lookup, addname,
getdents) and some of the additional logic to make it easier to
understand an dmodify the code.
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarBen Myers <bpm@sgi.com>
Signed-off-by: default avatarBen Myers <bpm@sgi.com>
parent 4bb20a83
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Showing with 209 additions and 177 deletions
fs/xfs/xfs_dir2_block.c
View file @ 20f7e9f3
......@@ -56,144 +56,60 @@ xfs_dir_startup(void)
xfs_dir_hash_dotdot = xfs_da_hashname((unsigned char *)"..", 2);
}
/*
* Add an entry to a block directory.
*/
int /* error */
xfs_dir2_block_addname(
xfs_da_args_t *args) /* directory op arguments */
static int
xfs_dir2_block_read(
struct xfs_trans *tp,
struct xfs_inode *dp,
struct xfs_buf **bpp)
{
xfs_dir2_data_free_t *bf; /* bestfree table in block */
xfs_dir2_data_hdr_t *hdr; /* block header */
xfs_dir2_leaf_entry_t *blp; /* block leaf entries */
struct xfs_buf *bp; /* buffer for block */
xfs_dir2_block_tail_t *btp; /* block tail */
int compact; /* need to compact leaf ents */
xfs_dir2_data_entry_t *dep; /* block data entry */
xfs_inode_t *dp; /* directory inode */
xfs_dir2_data_unused_t *dup; /* block unused entry */
int error; /* error return value */
xfs_dir2_data_unused_t *enddup=NULL; /* unused at end of data */
xfs_dahash_t hash; /* hash value of found entry */
int high; /* high index for binary srch */
int highstale; /* high stale index */
int lfloghigh=0; /* last final leaf to log */
int lfloglow=0; /* first final leaf to log */
int len; /* length of the new entry */
int low; /* low index for binary srch */
int lowstale; /* low stale index */
int mid=0; /* midpoint for binary srch */
xfs_mount_t *mp; /* filesystem mount point */
int needlog; /* need to log header */
int needscan; /* need to rescan freespace */
__be16 *tagp; /* pointer to tag value */
xfs_trans_t *tp; /* transaction structure */
struct xfs_mount *mp = dp->i_mount;
trace_xfs_dir2_block_addname(args);
dp = args->dp;
tp = args->trans;
mp = dp->i_mount;
/*
* Read the (one and only) directory block into dabuf bp.
*/
error = xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, &bp,
return xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, bpp,
XFS_DATA_FORK, NULL);
if (error)
return error;
ASSERT(bp != NULL);
hdr = bp->b_addr;
/*
* Check the magic number, corrupted if wrong.
*/
if (unlikely(hdr->magic != cpu_to_be32(XFS_DIR2_BLOCK_MAGIC))) {
XFS_CORRUPTION_ERROR("xfs_dir2_block_addname",
XFS_ERRLEVEL_LOW, mp, hdr);
xfs_trans_brelse(tp, bp);
return XFS_ERROR(EFSCORRUPTED);
}
len = xfs_dir2_data_entsize(args->namelen);
/*
* Set up pointers to parts of the block.
*/
}
static void
xfs_dir2_block_need_space(
struct xfs_dir2_data_hdr *hdr,
struct xfs_dir2_block_tail *btp,
struct xfs_dir2_leaf_entry *blp,
__be16 **tagpp,
struct xfs_dir2_data_unused **dupp,
struct xfs_dir2_data_unused **enddupp,
int *compact,
int len)
{
struct xfs_dir2_data_free *bf;
__be16 *tagp = NULL;
struct xfs_dir2_data_unused *dup = NULL;
struct xfs_dir2_data_unused *enddup = NULL;
*compact = 0;
bf = hdr->bestfree;
btp = xfs_dir2_block_tail_p(mp, hdr);
blp = xfs_dir2_block_leaf_p(btp);
/*
* No stale entries? Need space for entry and new leaf.
*/
if (!btp->stale) {
/*
* Tag just before the first leaf entry.
*/
tagp = (__be16 *)blp - 1;
/*
* Data object just before the first leaf entry.
*/
enddup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
/*
* If it's not free then can't do this add without cleaning up:
* the space before the first leaf entry needs to be free so it
* can be expanded to hold the pointer to the new entry.
*/
if (be16_to_cpu(enddup->freetag) != XFS_DIR2_DATA_FREE_TAG)
dup = enddup = NULL;
/*
* Check out the biggest freespace and see if it's the same one.
*/
else {
dup = (xfs_dir2_data_unused_t *)
((char *)hdr + be16_to_cpu(bf[0].offset));
if (dup == enddup) {
/*
* It is the biggest freespace, is it too small
* to hold the new leaf too?
*/
if (be16_to_cpu(dup->length) < len + (uint)sizeof(*blp)) {
/*
* Yes, we use the second-largest
* entry instead if it works.
*/
if (be16_to_cpu(bf[1].length) >= len)
dup = (xfs_dir2_data_unused_t *)
((char *)hdr +
be16_to_cpu(bf[1].offset));
else
dup = NULL;
}
} else {
/*
* Not the same free entry,
* just check its length.
* If there are stale entries we'll use one for the leaf.
*/
if (be16_to_cpu(dup->length) < len) {
dup = NULL;
}
}
}
compact = 0;
}
if (btp->stale) {
if (be16_to_cpu(bf[0].length) >= len) {
/*
* If there are stale entries we'll use one for the leaf.
* Is the biggest entry enough to avoid compaction?
* The biggest entry enough to avoid compaction.
*/
else if (be16_to_cpu(bf[0].length) >= len) {
dup = (xfs_dir2_data_unused_t *)
((char *)hdr + be16_to_cpu(bf[0].offset));
compact = 0;
goto out;
}
/*
* Will need to compact to make this work.
*/
else {
/*
* Tag just before the first leaf entry.
*/
*compact = 1;
tagp = (__be16 *)blp - 1;
/*
* Data object just before the first leaf entry.
*/
/* Data object just before the first leaf entry. */
dup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
/*
* If it's not free then the data will go where the
* leaf data starts now, if it works at all.
......@@ -206,58 +122,88 @@ xfs_dir2_block_addname(
dup = NULL;
else
dup = (xfs_dir2_data_unused_t *)blp;
compact = 1;
goto out;
}
/*
* If this isn't a real add, we're done with the buffer.
* no stale entries, so just use free space.
* Tag just before the first leaf entry.
*/
if (args->op_flags & XFS_DA_OP_JUSTCHECK)
xfs_trans_brelse(tp, bp);
tagp = (__be16 *)blp - 1;
/* Data object just before the first leaf entry. */
enddup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
/*
* If we don't have space for the new entry & leaf ...
* If it's not free then can't do this add without cleaning up:
* the space before the first leaf entry needs to be free so it
* can be expanded to hold the pointer to the new entry.
*/
if (!dup) {
if (be16_to_cpu(enddup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
/*
* Not trying to actually do anything, or don't have
* a space reservation: return no-space.
* Check out the biggest freespace and see if it's the same one.
*/
if ((args->op_flags & XFS_DA_OP_JUSTCHECK) || args->total == 0)
return XFS_ERROR(ENOSPC);
dup = (xfs_dir2_data_unused_t *)
((char *)hdr + be16_to_cpu(bf[0].offset));
if (dup != enddup) {
/*
* Convert to the next larger format.
* Then add the new entry in that format.
* Not the same free entry, just check its length.
*/
error = xfs_dir2_block_to_leaf(args, bp);
if (error)
return error;
return xfs_dir2_leaf_addname(args);
if (be16_to_cpu(dup->length) < len)
dup = NULL;
goto out;
}
/*
* Just checking, and it would work, so say so.
* It is the biggest freespace, can it hold the leaf too?
*/
if (args->op_flags & XFS_DA_OP_JUSTCHECK)
return 0;
needlog = needscan = 0;
if (be16_to_cpu(dup->length) < len + (uint)sizeof(*blp)) {
/*
* If need to compact the leaf entries, do it now.
* Yes, use the second-largest entry instead if it works.
*/
if (be16_to_cpu(bf[1].length) >= len)
dup = (xfs_dir2_data_unused_t *)
((char *)hdr + be16_to_cpu(bf[1].offset));
else
dup = NULL;
}
}
out:
*tagpp = tagp;
*dupp = dup;
*enddupp = enddup;
}
/*
* compact the leaf entries.
* Leave the highest-numbered stale entry stale.
* XXX should be the one closest to mid but mid is not yet computed.
*/
if (compact) {
static void
xfs_dir2_block_compact(
struct xfs_trans *tp,
struct xfs_buf *bp,
struct xfs_dir2_data_hdr *hdr,
struct xfs_dir2_block_tail *btp,
struct xfs_dir2_leaf_entry *blp,
int *needlog,
int *lfloghigh,
int *lfloglow)
{
int fromidx; /* source leaf index */
int toidx; /* target leaf index */
int needscan = 0;
int highstale; /* high stale index */
for (fromidx = toidx = be32_to_cpu(btp->count) - 1,
highstale = lfloghigh = -1;
fromidx >= 0;
fromidx--) {
if (blp[fromidx].address ==
cpu_to_be32(XFS_DIR2_NULL_DATAPTR)) {
fromidx = toidx = be32_to_cpu(btp->count) - 1;
highstale = *lfloghigh = -1;
for (; fromidx >= 0; fromidx--) {
if (blp[fromidx].address == cpu_to_be32(XFS_DIR2_NULL_DATAPTR)) {
if (highstale == -1)
highstale = toidx;
else {
if (lfloghigh == -1)
lfloghigh = toidx;
if (*lfloghigh == -1)
*lfloghigh = toidx;
continue;
}
}
......@@ -265,32 +211,126 @@ xfs_dir2_block_addname(
blp[toidx] = blp[fromidx];
toidx--;
}
lfloglow = toidx + 1 - (be32_to_cpu(btp->stale) - 1);
lfloghigh -= be32_to_cpu(btp->stale) - 1;
*lfloglow = toidx + 1 - (be32_to_cpu(btp->stale) - 1);
*lfloghigh -= be32_to_cpu(btp->stale) - 1;
be32_add_cpu(&btp->count, -(be32_to_cpu(btp->stale) - 1));
xfs_dir2_data_make_free(tp, bp,
(xfs_dir2_data_aoff_t)((char *)blp - (char *)hdr),
(xfs_dir2_data_aoff_t)((be32_to_cpu(btp->stale) - 1) * sizeof(*blp)),
&needlog, &needscan);
needlog, &needscan);
blp += be32_to_cpu(btp->stale) - 1;
btp->stale = cpu_to_be32(1);
/*
* If we now need to rebuild the bestfree map, do so.
* This needs to happen before the next call to use_free.
*/
if (needscan) {
xfs_dir2_data_freescan(mp, hdr, &needlog);
needscan = 0;
if (needscan)
xfs_dir2_data_freescan(tp->t_mountp, hdr, needlog);
}
/*
* Add an entry to a block directory.
*/
int /* error */
xfs_dir2_block_addname(
xfs_da_args_t *args) /* directory op arguments */
{
xfs_dir2_data_hdr_t *hdr; /* block header */
xfs_dir2_leaf_entry_t *blp; /* block leaf entries */
struct xfs_buf *bp; /* buffer for block */
xfs_dir2_block_tail_t *btp; /* block tail */
int compact; /* need to compact leaf ents */
xfs_dir2_data_entry_t *dep; /* block data entry */
xfs_inode_t *dp; /* directory inode */
xfs_dir2_data_unused_t *dup; /* block unused entry */
int error; /* error return value */
xfs_dir2_data_unused_t *enddup=NULL; /* unused at end of data */
xfs_dahash_t hash; /* hash value of found entry */
int high; /* high index for binary srch */
int highstale; /* high stale index */
int lfloghigh=0; /* last final leaf to log */
int lfloglow=0; /* first final leaf to log */
int len; /* length of the new entry */
int low; /* low index for binary srch */
int lowstale; /* low stale index */
int mid=0; /* midpoint for binary srch */
xfs_mount_t *mp; /* filesystem mount point */
int needlog; /* need to log header */
int needscan; /* need to rescan freespace */
__be16 *tagp; /* pointer to tag value */
xfs_trans_t *tp; /* transaction structure */
trace_xfs_dir2_block_addname(args);
dp = args->dp;
tp = args->trans;
mp = dp->i_mount;
/* Read the (one and only) directory block into bp. */
error = xfs_dir2_block_read(tp, dp, &bp);
if (error)
return error;
len = xfs_dir2_data_entsize(args->namelen);
/*
* Set up pointers to parts of the block.
*/
hdr = bp->b_addr;
btp = xfs_dir2_block_tail_p(mp, hdr);
blp = xfs_dir2_block_leaf_p(btp);
/*
* Find out if we can reuse stale entries or whether we need extra
* space for entry and new leaf.
*/
xfs_dir2_block_need_space(hdr, btp, blp, &tagp, &dup,
&enddup, &compact, len);
/*
* Done everything we need for a space check now.
*/
if (args->op_flags & XFS_DA_OP_JUSTCHECK) {
xfs_trans_brelse(tp, bp);
if (!dup)
return XFS_ERROR(ENOSPC);
return 0;
}
/*
* If we don't have space for the new entry & leaf ...
*/
if (!dup) {
/* Don't have a space reservation: return no-space. */
if (args->total == 0)
return XFS_ERROR(ENOSPC);
/*
* Convert to the next larger format.
* Then add the new entry in that format.
*/
error = xfs_dir2_block_to_leaf(args, bp);
if (error)
return error;
return xfs_dir2_leaf_addname(args);
}
needlog = needscan = 0;
/*
* If need to compact the leaf entries, do it now.
*/
if (compact)
xfs_dir2_block_compact(tp, bp, hdr, btp, blp, &needlog,
&lfloghigh, &lfloglow);
else if (btp->stale) {
/*
* Set leaf logging boundaries to impossible state.
* For the no-stale case they're set explicitly.
*/
else if (btp->stale) {
lfloglow = be32_to_cpu(btp->count);
lfloghigh = -1;
}
/*
* Find the slot that's first lower than our hash value, -1 if none.
*/
......@@ -450,18 +490,13 @@ xfs_dir2_block_getdents(
/*
* If the block number in the offset is out of range, we're done.
*/
if (xfs_dir2_dataptr_to_db(mp, *offset) > mp->m_dirdatablk) {
if (xfs_dir2_dataptr_to_db(mp, *offset) > mp->m_dirdatablk)
return 0;
}
/*
* Can't read the block, give up, else get dabuf in bp.
*/
error = xfs_da_read_buf(NULL, dp, mp->m_dirdatablk, -1,
&bp, XFS_DATA_FORK, NULL);
error = xfs_dir2_block_read(NULL, dp, &bp);
if (error)
return error;
ASSERT(bp != NULL);
/*
* Extract the byte offset we start at from the seek pointer.
* We'll skip entries before this.
......@@ -637,14 +672,11 @@ xfs_dir2_block_lookup_int(
dp = args->dp;
tp = args->trans;
mp = dp->i_mount;
/*
* Read the buffer, return error if we can't get it.
*/
error = xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, &bp,
XFS_DATA_FORK, NULL);
error = xfs_dir2_block_read(tp, dp, &bp);
if (error)
return error;
ASSERT(bp != NULL);
hdr = bp->b_addr;
xfs_dir2_data_check(dp, bp);
btp = xfs_dir2_block_tail_p(mp, hdr);
......
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