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a45086e27d
linux/fs/xfs/libxfs/xfs_dir2_data.c
Brian Foster a45086e27d xfs: validate metadata LSNs against log on v5 superblocks 
Since the onset of v5 superblocks, the LSN of the last modification has
been included in a variety of on-disk data structures. This LSN is used
to provide log recovery ordering guarantees (e.g., to ensure an older
log recovery item is not replayed over a newer target data structure).

While this works correctly from the point a filesystem is formatted and
mounted, userspace tools have some problematic behaviors that defeat
this mechanism. For example, xfs_repair historically zeroes out the log
unconditionally (regardless of whether corruption is detected). If this
occurs, the LSN of the filesystem is reset and the log is now in a
problematic state with respect to on-disk metadata structures that might
have a larger LSN. Until either the log catches up to the highest
previously used metadata LSN or each affected data structure is modified
and written out without incident (which resets the metadata LSN), log
recovery is susceptible to filesystem corruption.

This problem is ultimately addressed and repaired in the associated
userspace tools. The kernel is still responsible to detect the problem
and notify the user that something is wrong. Check the superblock LSN at
mount time and fail the mount if it is invalid. From that point on,
trigger verifier failure on any metadata I/O where an invalid LSN is
detected. This results in a filesystem shutdown and guarantees that we
do not log metadata changes with invalid LSNs on disk. Since this is a
known issue with a known recovery path, present a warning to instruct
the user how to recover.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2015-10-12 15:59:25 +11:00

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/*
* Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
* Copyright (c) 2013 Red Hat, 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_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_inode.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_error.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"
#include "xfs_cksum.h"
#include "xfs_log.h"
/*
* Check the consistency of the data block.
* The input can also be a block-format directory.
* Return 0 is the buffer is good, otherwise an error.
*/
int
__xfs_dir3_data_check(
struct xfs_inode *dp, /* incore inode pointer */
struct xfs_buf *bp) /* data block's buffer */
{
xfs_dir2_dataptr_t addr; /* addr for leaf lookup */
xfs_dir2_data_free_t *bf; /* bestfree table */
xfs_dir2_block_tail_t *btp=NULL; /* block tail */
int count; /* count of entries found */
xfs_dir2_data_hdr_t *hdr; /* data block header */
xfs_dir2_data_entry_t *dep; /* data entry */
xfs_dir2_data_free_t *dfp; /* bestfree entry */
xfs_dir2_data_unused_t *dup; /* unused entry */
char *endp; /* end of useful data */
int freeseen; /* mask of bestfrees seen */
xfs_dahash_t hash; /* hash of current name */
int i; /* leaf index */
int lastfree; /* last entry was unused */
xfs_dir2_leaf_entry_t *lep=NULL; /* block leaf entries */
xfs_mount_t *mp; /* filesystem mount point */
char *p; /* current data position */
int stale; /* count of stale leaves */
struct xfs_name name;
const struct xfs_dir_ops *ops;
struct xfs_da_geometry *geo;
mp = bp->b_target->bt_mount;
geo = mp->m_dir_geo;
/*
* We can be passed a null dp here from a verifier, so we need to go the
* hard way to get them.
*/
ops = xfs_dir_get_ops(mp, dp);
hdr = bp->b_addr;
p = (char *)ops->data_entry_p(hdr);
switch (hdr->magic) {
case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
btp = xfs_dir2_block_tail_p(geo, hdr);
lep = xfs_dir2_block_leaf_p(btp);
endp = (char *)lep;
/*
* The number of leaf entries is limited by the size of the
* block and the amount of space used by the data entries.
* We don't know how much space is used by the data entries yet,
* so just ensure that the count falls somewhere inside the
* block right now.
*/
XFS_WANT_CORRUPTED_RETURN(mp, be32_to_cpu(btp->count) <
((char *)btp - p) / sizeof(struct xfs_dir2_leaf_entry));
break;
case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
endp = (char *)hdr + geo->blksize;
break;
default:
XFS_ERROR_REPORT("Bad Magic", XFS_ERRLEVEL_LOW, mp);
return -EFSCORRUPTED;
}
/*
* Account for zero bestfree entries.
*/
bf = ops->data_bestfree_p(hdr);
count = lastfree = freeseen = 0;
if (!bf[0].length) {
XFS_WANT_CORRUPTED_RETURN(mp, !bf[0].offset);
freeseen |= 1 << 0;
}
if (!bf[1].length) {
XFS_WANT_CORRUPTED_RETURN(mp, !bf[1].offset);
freeseen |= 1 << 1;
}
if (!bf[2].length) {
XFS_WANT_CORRUPTED_RETURN(mp, !bf[2].offset);
freeseen |= 1 << 2;
}
XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[0].length) >=
be16_to_cpu(bf[1].length));
XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[1].length) >=
be16_to_cpu(bf[2].length));
/*
* Loop over the data/unused entries.
*/
while (p < endp) {
dup = (xfs_dir2_data_unused_t *)p;
/*
* If it's unused, look for the space in the bestfree table.
* If we find it, account for that, else make sure it
* doesn't need to be there.
*/
if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
XFS_WANT_CORRUPTED_RETURN(mp, lastfree == 0);
XFS_WANT_CORRUPTED_RETURN(mp,
be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)) ==
(char *)dup - (char *)hdr);
dfp = xfs_dir2_data_freefind(hdr, bf, dup);
if (dfp) {
i = (int)(dfp - bf);
XFS_WANT_CORRUPTED_RETURN(mp,
(freeseen & (1 << i)) == 0);
freeseen |= 1 << i;
} else {
XFS_WANT_CORRUPTED_RETURN(mp,
be16_to_cpu(dup->length) <=
be16_to_cpu(bf[2].length));
}
p += be16_to_cpu(dup->length);
lastfree = 1;
continue;
}
/*
* It's a real entry. Validate the fields.
* If this is a block directory then make sure it's
* in the leaf section of the block.
* The linear search is crude but this is DEBUG code.
*/
dep = (xfs_dir2_data_entry_t *)p;
XFS_WANT_CORRUPTED_RETURN(mp, dep->namelen != 0);
XFS_WANT_CORRUPTED_RETURN(mp,
!xfs_dir_ino_validate(mp, be64_to_cpu(dep->inumber)));
XFS_WANT_CORRUPTED_RETURN(mp,
be16_to_cpu(*ops->data_entry_tag_p(dep)) ==
(char *)dep - (char *)hdr);
XFS_WANT_CORRUPTED_RETURN(mp,
ops->data_get_ftype(dep) < XFS_DIR3_FT_MAX);
count++;
lastfree = 0;
if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
addr = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
(xfs_dir2_data_aoff_t)
((char *)dep - (char *)hdr));
name.name = dep->name;
name.len = dep->namelen;
hash = mp->m_dirnameops->hashname(&name);
for (i = 0; i < be32_to_cpu(btp->count); i++) {
if (be32_to_cpu(lep[i].address) == addr &&
be32_to_cpu(lep[i].hashval) == hash)
break;
}
XFS_WANT_CORRUPTED_RETURN(mp,
i < be32_to_cpu(btp->count));
}
p += ops->data_entsize(dep->namelen);
}
/*
* Need to have seen all the entries and all the bestfree slots.
*/
XFS_WANT_CORRUPTED_RETURN(mp, freeseen == 7);
if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
for (i = stale = 0; i < be32_to_cpu(btp->count); i++) {
if (lep[i].address ==
cpu_to_be32(XFS_DIR2_NULL_DATAPTR))
stale++;
if (i > 0)
XFS_WANT_CORRUPTED_RETURN(mp,
be32_to_cpu(lep[i].hashval) >=
be32_to_cpu(lep[i - 1].hashval));
}
XFS_WANT_CORRUPTED_RETURN(mp, count ==
be32_to_cpu(btp->count) - be32_to_cpu(btp->stale));
XFS_WANT_CORRUPTED_RETURN(mp, stale == be32_to_cpu(btp->stale));
}
return 0;
}
static bool
xfs_dir3_data_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
if (xfs_sb_version_hascrc(&mp->m_sb)) {
if (hdr3->magic != cpu_to_be32(XFS_DIR3_DATA_MAGIC))
return false;
if (!uuid_equal(&hdr3->uuid, &mp->m_sb.sb_meta_uuid))
return false;
if (be64_to_cpu(hdr3->blkno) != bp->b_bn)
return false;
if (!xfs_log_check_lsn(mp, be64_to_cpu(hdr3->lsn)))
return false;
} else {
if (hdr3->magic != cpu_to_be32(XFS_DIR2_DATA_MAGIC))
return false;
}
if (__xfs_dir3_data_check(NULL, bp))
return false;
return true;
}
/*
* Readahead of the first block of the directory when it is opened is completely
* oblivious to the format of the directory. Hence we can either get a block
* format buffer or a data format buffer on readahead.
*/
static void
xfs_dir3_data_reada_verify(
struct xfs_buf *bp)
{
struct xfs_dir2_data_hdr *hdr = bp->b_addr;
switch (hdr->magic) {
case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):
case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):
bp->b_ops = &xfs_dir3_block_buf_ops;
bp->b_ops->verify_read(bp);
return;
case cpu_to_be32(XFS_DIR2_DATA_MAGIC):
case cpu_to_be32(XFS_DIR3_DATA_MAGIC):
bp->b_ops = &xfs_dir3_data_buf_ops;
bp->b_ops->verify_read(bp);
return;
default:
xfs_buf_ioerror(bp, -EFSCORRUPTED);
xfs_verifier_error(bp);
break;
}
}
static void
xfs_dir3_data_read_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
if (xfs_sb_version_hascrc(&mp->m_sb) &&
!xfs_buf_verify_cksum(bp, XFS_DIR3_DATA_CRC_OFF))
xfs_buf_ioerror(bp, -EFSBADCRC);
else if (!xfs_dir3_data_verify(bp))
xfs_buf_ioerror(bp, -EFSCORRUPTED);
if (bp->b_error)
xfs_verifier_error(bp);
}
static void
xfs_dir3_data_write_verify(
struct xfs_buf *bp)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_buf_log_item *bip = bp->b_fspriv;
struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
if (!xfs_dir3_data_verify(bp)) {
xfs_buf_ioerror(bp, -EFSCORRUPTED);
xfs_verifier_error(bp);
return;
}
if (!xfs_sb_version_hascrc(&mp->m_sb))
return;
if (bip)
hdr3->lsn = cpu_to_be64(bip->bli_item.li_lsn);
xfs_buf_update_cksum(bp, XFS_DIR3_DATA_CRC_OFF);
}
const struct xfs_buf_ops xfs_dir3_data_buf_ops = {
.verify_read = xfs_dir3_data_read_verify,
.verify_write = xfs_dir3_data_write_verify,
};
static const struct xfs_buf_ops xfs_dir3_data_reada_buf_ops = {
.verify_read = xfs_dir3_data_reada_verify,
.verify_write = xfs_dir3_data_write_verify,
};
int
xfs_dir3_data_read(
struct xfs_trans *tp,
struct xfs_inode *dp,
xfs_dablk_t bno,
xfs_daddr_t mapped_bno,
struct xfs_buf **bpp)
{
int err;
err = xfs_da_read_buf(tp, dp, bno, mapped_bno, bpp,
XFS_DATA_FORK, &xfs_dir3_data_buf_ops);
if (!err && tp)
xfs_trans_buf_set_type(tp, *bpp, XFS_BLFT_DIR_DATA_BUF);
return err;
}
int
xfs_dir3_data_readahead(
struct xfs_inode *dp,
xfs_dablk_t bno,
xfs_daddr_t mapped_bno)
{
return xfs_da_reada_buf(dp, bno, mapped_bno,
XFS_DATA_FORK, &xfs_dir3_data_reada_buf_ops);
}
/*
* Given a data block and an unused entry from that block,
* return the bestfree entry if any that corresponds to it.
*/
xfs_dir2_data_free_t *
xfs_dir2_data_freefind(
struct xfs_dir2_data_hdr *hdr, /* data block header */
struct xfs_dir2_data_free *bf, /* bestfree table pointer */
struct xfs_dir2_data_unused *dup) /* unused space */
{
xfs_dir2_data_free_t *dfp; /* bestfree entry */
xfs_dir2_data_aoff_t off; /* offset value needed */
#ifdef DEBUG
int matched; /* matched the value */
int seenzero; /* saw a 0 bestfree entry */
#endif
off = (xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr);
#ifdef DEBUG
/*
* Validate some consistency in the bestfree table.
* Check order, non-overlapping entries, and if we find the
* one we're looking for it has to be exact.
*/
ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
for (dfp = &bf[0], seenzero = matched = 0;
dfp < &bf[XFS_DIR2_DATA_FD_COUNT];
dfp++) {
if (!dfp->offset) {
ASSERT(!dfp->length);
seenzero = 1;
continue;
}
ASSERT(seenzero == 0);
if (be16_to_cpu(dfp->offset) == off) {
matched = 1;
ASSERT(dfp->length == dup->length);
} else if (off < be16_to_cpu(dfp->offset))
ASSERT(off + be16_to_cpu(dup->length) <= be16_to_cpu(dfp->offset));
else
ASSERT(be16_to_cpu(dfp->offset) + be16_to_cpu(dfp->length) <= off);
ASSERT(matched || be16_to_cpu(dfp->length) >= be16_to_cpu(dup->length));
if (dfp > &bf[0])
ASSERT(be16_to_cpu(dfp[-1].length) >= be16_to_cpu(dfp[0].length));
}
#endif
/*
* If this is smaller than the smallest bestfree entry,
* it can't be there since they're sorted.
*/
if (be16_to_cpu(dup->length) <
be16_to_cpu(bf[XFS_DIR2_DATA_FD_COUNT - 1].length))
return NULL;
/*
* Look at the three bestfree entries for our guy.
*/
for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
if (!dfp->offset)
return NULL;
if (be16_to_cpu(dfp->offset) == off)
return dfp;
}
/*
* Didn't find it. This only happens if there are duplicate lengths.
*/
return NULL;
}
/*
* Insert an unused-space entry into the bestfree table.
*/
xfs_dir2_data_free_t * /* entry inserted */
xfs_dir2_data_freeinsert(
struct xfs_dir2_data_hdr *hdr, /* data block pointer */
struct xfs_dir2_data_free *dfp, /* bestfree table pointer */
struct xfs_dir2_data_unused *dup, /* unused space */
int *loghead) /* log the data header (out) */
{
xfs_dir2_data_free_t new; /* new bestfree entry */
ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
new.length = dup->length;
new.offset = cpu_to_be16((char *)dup - (char *)hdr);
/*
* Insert at position 0, 1, or 2; or not at all.
*/
if (be16_to_cpu(new.length) > be16_to_cpu(dfp[0].length)) {
dfp[2] = dfp[1];
dfp[1] = dfp[0];
dfp[0] = new;
*loghead = 1;
return &dfp[0];
}
if (be16_to_cpu(new.length) > be16_to_cpu(dfp[1].length)) {
dfp[2] = dfp[1];
dfp[1] = new;
*loghead = 1;
return &dfp[1];
}
if (be16_to_cpu(new.length) > be16_to_cpu(dfp[2].length)) {
dfp[2] = new;
*loghead = 1;
return &dfp[2];
}
return NULL;
}
/*
* Remove a bestfree entry from the table.
*/
STATIC void
xfs_dir2_data_freeremove(
struct xfs_dir2_data_hdr *hdr, /* data block header */
struct xfs_dir2_data_free *bf, /* bestfree table pointer */
struct xfs_dir2_data_free *dfp, /* bestfree entry pointer */
int *loghead) /* out: log data header */
{
ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
/*
* It's the first entry, slide the next 2 up.
*/
if (dfp == &bf[0]) {
bf[0] = bf[1];
bf[1] = bf[2];
}
/*
* It's the second entry, slide the 3rd entry up.
*/
else if (dfp == &bf[1])
bf[1] = bf[2];
/*
* Must be the last entry.
*/
else
ASSERT(dfp == &bf[2]);
/*
* Clear the 3rd entry, must be zero now.
*/
bf[2].length = 0;
bf[2].offset = 0;
*loghead = 1;
}
/*
* Given a data block, reconstruct its bestfree map.
*/
void
xfs_dir2_data_freescan(
struct xfs_inode *dp,
struct xfs_dir2_data_hdr *hdr,
int *loghead)
{
xfs_dir2_block_tail_t *btp; /* block tail */
xfs_dir2_data_entry_t *dep; /* active data entry */
xfs_dir2_data_unused_t *dup; /* unused data entry */
struct xfs_dir2_data_free *bf;
char *endp; /* end of block's data */
char *p; /* current entry pointer */
struct xfs_da_geometry *geo = dp->i_mount->m_dir_geo;
ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
/*
* Start by clearing the table.
*/
bf = dp->d_ops->data_bestfree_p(hdr);
memset(bf, 0, sizeof(*bf) * XFS_DIR2_DATA_FD_COUNT);
*loghead = 1;
/*
* Set up pointers.
*/
p = (char *)dp->d_ops->data_entry_p(hdr);
if (hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
btp = xfs_dir2_block_tail_p(geo, hdr);
endp = (char *)xfs_dir2_block_leaf_p(btp);
} else
endp = (char *)hdr + geo->blksize;
/*
* Loop over the block's entries.
*/
while (p < endp) {
dup = (xfs_dir2_data_unused_t *)p;
/*
* If it's a free entry, insert it.
*/
if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
ASSERT((char *)dup - (char *)hdr ==
be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
xfs_dir2_data_freeinsert(hdr, bf, dup, loghead);
p += be16_to_cpu(dup->length);
}
/*
* For active entries, check their tags and skip them.
*/
else {
dep = (xfs_dir2_data_entry_t *)p;
ASSERT((char *)dep - (char *)hdr ==
be16_to_cpu(*dp->d_ops->data_entry_tag_p(dep)));
p += dp->d_ops->data_entsize(dep->namelen);
}
}
}
/*
* Initialize a data block at the given block number in the directory.
* Give back the buffer for the created block.
*/
int /* error */
xfs_dir3_data_init(
xfs_da_args_t *args, /* directory operation args */
xfs_dir2_db_t blkno, /* logical dir block number */
struct xfs_buf **bpp) /* output block buffer */
{
struct xfs_buf *bp; /* block buffer */
xfs_dir2_data_hdr_t *hdr; /* data block header */
xfs_inode_t *dp; /* incore directory inode */
xfs_dir2_data_unused_t *dup; /* unused entry pointer */
struct xfs_dir2_data_free *bf;
int error; /* error return value */
int i; /* bestfree index */
xfs_mount_t *mp; /* filesystem mount point */
xfs_trans_t *tp; /* transaction pointer */
int t; /* temp */
dp = args->dp;
mp = dp->i_mount;
tp = args->trans;
/*
* Get the buffer set up for the block.
*/
error = xfs_da_get_buf(tp, dp, xfs_dir2_db_to_da(args->geo, blkno),
-1, &bp, XFS_DATA_FORK);
if (error)
return error;
bp->b_ops = &xfs_dir3_data_buf_ops;
xfs_trans_buf_set_type(tp, bp, XFS_BLFT_DIR_DATA_BUF);
/*
* Initialize the header.
*/
hdr = bp->b_addr;
if (xfs_sb_version_hascrc(&mp->m_sb)) {
struct xfs_dir3_blk_hdr *hdr3 = bp->b_addr;
memset(hdr3, 0, sizeof(*hdr3));
hdr3->magic = cpu_to_be32(XFS_DIR3_DATA_MAGIC);
hdr3->blkno = cpu_to_be64(bp->b_bn);
hdr3->owner = cpu_to_be64(dp->i_ino);
uuid_copy(&hdr3->uuid, &mp->m_sb.sb_meta_uuid);
} else
hdr->magic = cpu_to_be32(XFS_DIR2_DATA_MAGIC);
bf = dp->d_ops->data_bestfree_p(hdr);
bf[0].offset = cpu_to_be16(dp->d_ops->data_entry_offset);
for (i = 1; i < XFS_DIR2_DATA_FD_COUNT; i++) {
bf[i].length = 0;
bf[i].offset = 0;
}
/*
* Set up an unused entry for the block's body.
*/
dup = dp->d_ops->data_unused_p(hdr);
dup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
t = args->geo->blksize - (uint)dp->d_ops->data_entry_offset;
bf[0].length = cpu_to_be16(t);
dup->length = cpu_to_be16(t);
*xfs_dir2_data_unused_tag_p(dup) = cpu_to_be16((char *)dup - (char *)hdr);
/*
* Log it and return it.
*/
xfs_dir2_data_log_header(args, bp);
xfs_dir2_data_log_unused(args, bp, dup);
*bpp = bp;
return 0;
}
/*
* Log an active data entry from the block.
*/
void
xfs_dir2_data_log_entry(
struct xfs_da_args *args,
struct xfs_buf *bp,
xfs_dir2_data_entry_t *dep) /* data entry pointer */
{
struct xfs_dir2_data_hdr *hdr = bp->b_addr;
ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
xfs_trans_log_buf(args->trans, bp, (uint)((char *)dep - (char *)hdr),
(uint)((char *)(args->dp->d_ops->data_entry_tag_p(dep) + 1) -
(char *)hdr - 1));
}
/*
* Log a data block header.
*/
void
xfs_dir2_data_log_header(
struct xfs_da_args *args,
struct xfs_buf *bp)
{
#ifdef DEBUG
struct xfs_dir2_data_hdr *hdr = bp->b_addr;
ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
#endif
xfs_trans_log_buf(args->trans, bp, 0,
args->dp->d_ops->data_entry_offset - 1);
}
/*
* Log a data unused entry.
*/
void
xfs_dir2_data_log_unused(
struct xfs_da_args *args,
struct xfs_buf *bp,
xfs_dir2_data_unused_t *dup) /* data unused pointer */
{
xfs_dir2_data_hdr_t *hdr = bp->b_addr;
ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
/*
* Log the first part of the unused entry.
*/
xfs_trans_log_buf(args->trans, bp, (uint)((char *)dup - (char *)hdr),
(uint)((char *)&dup->length + sizeof(dup->length) -
1 - (char *)hdr));
/*
* Log the end (tag) of the unused entry.
*/
xfs_trans_log_buf(args->trans, bp,
(uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr),
(uint)((char *)xfs_dir2_data_unused_tag_p(dup) - (char *)hdr +
sizeof(xfs_dir2_data_off_t) - 1));
}
/*
* Make a byte range in the data block unused.
* Its current contents are unimportant.
*/
void
xfs_dir2_data_make_free(
struct xfs_da_args *args,
struct xfs_buf *bp,
xfs_dir2_data_aoff_t offset, /* starting byte offset */
xfs_dir2_data_aoff_t len, /* length in bytes */
int *needlogp, /* out: log header */
int *needscanp) /* out: regen bestfree */
{
xfs_dir2_data_hdr_t *hdr; /* data block pointer */
xfs_dir2_data_free_t *dfp; /* bestfree pointer */
char *endptr; /* end of data area */
int needscan; /* need to regen bestfree */
xfs_dir2_data_unused_t *newdup; /* new unused entry */
xfs_dir2_data_unused_t *postdup; /* unused entry after us */
xfs_dir2_data_unused_t *prevdup; /* unused entry before us */
struct xfs_dir2_data_free *bf;
hdr = bp->b_addr;
/*
* Figure out where the end of the data area is.
*/
if (hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC))
endptr = (char *)hdr + args->geo->blksize;
else {
xfs_dir2_block_tail_t *btp; /* block tail */
ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
btp = xfs_dir2_block_tail_p(args->geo, hdr);
endptr = (char *)xfs_dir2_block_leaf_p(btp);
}
/*
* If this isn't the start of the block, then back up to
* the previous entry and see if it's free.
*/
if (offset > args->dp->d_ops->data_entry_offset) {
__be16 *tagp; /* tag just before us */
tagp = (__be16 *)((char *)hdr + offset) - 1;
prevdup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));
if (be16_to_cpu(prevdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
prevdup = NULL;
} else
prevdup = NULL;
/*
* If this isn't the end of the block, see if the entry after
* us is free.
*/
if ((char *)hdr + offset + len < endptr) {
postdup =
(xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
if (be16_to_cpu(postdup->freetag) != XFS_DIR2_DATA_FREE_TAG)
postdup = NULL;
} else
postdup = NULL;
ASSERT(*needscanp == 0);
needscan = 0;
/*
* Previous and following entries are both free,
* merge everything into a single free entry.
*/
bf = args->dp->d_ops->data_bestfree_p(hdr);
if (prevdup && postdup) {
xfs_dir2_data_free_t *dfp2; /* another bestfree pointer */
/*
* See if prevdup and/or postdup are in bestfree table.
*/
dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
dfp2 = xfs_dir2_data_freefind(hdr, bf, postdup);
/*
* We need a rescan unless there are exactly 2 free entries
* namely our two. Then we know what's happening, otherwise
* since the third bestfree is there, there might be more
* entries.
*/
needscan = (bf[2].length != 0);
/*
* Fix up the new big freespace.
*/
be16_add_cpu(&prevdup->length, len + be16_to_cpu(postdup->length));
*xfs_dir2_data_unused_tag_p(prevdup) =
cpu_to_be16((char *)prevdup - (char *)hdr);
xfs_dir2_data_log_unused(args, bp, prevdup);
if (!needscan) {
/*
* Has to be the case that entries 0 and 1 are
* dfp and dfp2 (don't know which is which), and
* entry 2 is empty.
* Remove entry 1 first then entry 0.
*/
ASSERT(dfp && dfp2);
if (dfp == &bf[1]) {
dfp = &bf[0];
ASSERT(dfp2 == dfp);
dfp2 = &bf[1];
}
xfs_dir2_data_freeremove(hdr, bf, dfp2, needlogp);
xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
/*
* Now insert the new entry.
*/
dfp = xfs_dir2_data_freeinsert(hdr, bf, prevdup,
needlogp);
ASSERT(dfp == &bf[0]);
ASSERT(dfp->length == prevdup->length);
ASSERT(!dfp[1].length);
ASSERT(!dfp[2].length);
}
}
/*
* The entry before us is free, merge with it.
*/
else if (prevdup) {
dfp = xfs_dir2_data_freefind(hdr, bf, prevdup);
be16_add_cpu(&prevdup->length, len);
*xfs_dir2_data_unused_tag_p(prevdup) =
cpu_to_be16((char *)prevdup - (char *)hdr);
xfs_dir2_data_log_unused(args, bp, prevdup);
/*
* If the previous entry was in the table, the new entry
* is longer, so it will be in the table too. Remove
* the old one and add the new one.
*/
if (dfp) {
xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
xfs_dir2_data_freeinsert(hdr, bf, prevdup, needlogp);
}
/*
* Otherwise we need a scan if the new entry is big enough.
*/
else {
needscan = be16_to_cpu(prevdup->length) >
be16_to_cpu(bf[2].length);
}
}
/*
* The following entry is free, merge with it.
*/
else if (postdup) {
dfp = xfs_dir2_data_freefind(hdr, bf, postdup);
newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
newdup->length = cpu_to_be16(len + be16_to_cpu(postdup->length));
*xfs_dir2_data_unused_tag_p(newdup) =
cpu_to_be16((char *)newdup - (char *)hdr);
xfs_dir2_data_log_unused(args, bp, newdup);
/*
* If the following entry was in the table, the new entry
* is longer, so it will be in the table too. Remove
* the old one and add the new one.
*/
if (dfp) {
xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
}
/*
* Otherwise we need a scan if the new entry is big enough.
*/
else {
needscan = be16_to_cpu(newdup->length) >
be16_to_cpu(bf[2].length);
}
}
/*
* Neither neighbor is free. Make a new entry.
*/
else {
newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset);
newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
newdup->length = cpu_to_be16(len);
*xfs_dir2_data_unused_tag_p(newdup) =
cpu_to_be16((char *)newdup - (char *)hdr);
xfs_dir2_data_log_unused(args, bp, newdup);
xfs_dir2_data_freeinsert(hdr, bf, newdup, needlogp);
}
*needscanp = needscan;
}
/*
* Take a byte range out of an existing unused space and make it un-free.
*/
void
xfs_dir2_data_use_free(
struct xfs_da_args *args,
struct xfs_buf *bp,
xfs_dir2_data_unused_t *dup, /* unused entry */
xfs_dir2_data_aoff_t offset, /* starting offset to use */
xfs_dir2_data_aoff_t len, /* length to use */
int *needlogp, /* out: need to log header */
int *needscanp) /* out: need regen bestfree */
{
xfs_dir2_data_hdr_t *hdr; /* data block header */
xfs_dir2_data_free_t *dfp; /* bestfree pointer */
int matchback; /* matches end of freespace */
int matchfront; /* matches start of freespace */
int needscan; /* need to regen bestfree */
xfs_dir2_data_unused_t *newdup; /* new unused entry */
xfs_dir2_data_unused_t *newdup2; /* another new unused entry */
int oldlen; /* old unused entry's length */
struct xfs_dir2_data_free *bf;
hdr = bp->b_addr;
ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR2_BLOCK_MAGIC) ||
hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC));
ASSERT(be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG);
ASSERT(offset >= (char *)dup - (char *)hdr);
ASSERT(offset + len <= (char *)dup + be16_to_cpu(dup->length) - (char *)hdr);
ASSERT((char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)));
/*
* Look up the entry in the bestfree table.
*/
oldlen = be16_to_cpu(dup->length);
bf = args->dp->d_ops->data_bestfree_p(hdr);
dfp = xfs_dir2_data_freefind(hdr, bf, dup);
ASSERT(dfp || oldlen <= be16_to_cpu(bf[2].length));
/*
* Check for alignment with front and back of the entry.
*/
matchfront = (char *)dup - (char *)hdr == offset;
matchback = (char *)dup + oldlen - (char *)hdr == offset + len;
ASSERT(*needscanp == 0);
needscan = 0;
/*
* If we matched it exactly we just need to get rid of it from
* the bestfree table.
*/
if (matchfront && matchback) {
if (dfp) {
needscan = (bf[2].offset != 0);
if (!needscan)
xfs_dir2_data_freeremove(hdr, bf, dfp,
needlogp);
}
}
/*
* We match the first part of the entry.
* Make a new entry with the remaining freespace.
*/
else if (matchfront) {
newdup = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
newdup->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
newdup->length = cpu_to_be16(oldlen - len);
*xfs_dir2_data_unused_tag_p(newdup) =
cpu_to_be16((char *)newdup - (char *)hdr);
xfs_dir2_data_log_unused(args, bp, newdup);
/*
* If it was in the table, remove it and add the new one.
*/
if (dfp) {
xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
needlogp);
ASSERT(dfp != NULL);
ASSERT(dfp->length == newdup->length);
ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
/*
* If we got inserted at the last slot,
* that means we don't know if there was a better
* choice for the last slot, or not. Rescan.
*/
needscan = dfp == &bf[2];
}
}
/*
* We match the last part of the entry.
* Trim the allocated space off the tail of the entry.
*/
else if (matchback) {
newdup = dup;
newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
*xfs_dir2_data_unused_tag_p(newdup) =
cpu_to_be16((char *)newdup - (char *)hdr);
xfs_dir2_data_log_unused(args, bp, newdup);
/*
* If it was in the table, remove it and add the new one.
*/
if (dfp) {
xfs_dir2_data_freeremove(hdr, bf, dfp, needlogp);
dfp = xfs_dir2_data_freeinsert(hdr, bf, newdup,
needlogp);
ASSERT(dfp != NULL);
ASSERT(dfp->length == newdup->length);
ASSERT(be16_to_cpu(dfp->offset) == (char *)newdup - (char *)hdr);
/*
* If we got inserted at the last slot,
* that means we don't know if there was a better
* choice for the last slot, or not. Rescan.
*/
needscan = dfp == &bf[2];
}
}
/*
* Poking out the middle of an entry.
* Make two new entries.
*/
else {
newdup = dup;
newdup->length = cpu_to_be16(((char *)hdr + offset) - (char *)newdup);
*xfs_dir2_data_unused_tag_p(newdup) =
cpu_to_be16((char *)newdup - (char *)hdr);
xfs_dir2_data_log_unused(args, bp, newdup);
newdup2 = (xfs_dir2_data_unused_t *)((char *)hdr + offset + len);
newdup2->freetag = cpu_to_be16(XFS_DIR2_DATA_FREE_TAG);
newdup2->length = cpu_to_be16(oldlen - len - be16_to_cpu(newdup->length));
*xfs_dir2_data_unused_tag_p(newdup2) =
cpu_to_be16((char *)newdup2 - (char *)hdr);
xfs_dir2_data_log_unused(args, bp, newdup2);
/*
* If the old entry was in the table, we need to scan
* if the 3rd entry was valid, since these entries
* are smaller than the old one.
* If we don't need to scan that means there were 1 or 2
* entries in the table, and removing the old and adding
* the 2 new will work.
*/
if (dfp) {
needscan = (bf[2].length != 0);
if (!needscan) {
xfs_dir2_data_freeremove(hdr, bf, dfp,
needlogp);
xfs_dir2_data_freeinsert(hdr, bf, newdup,
needlogp);
xfs_dir2_data_freeinsert(hdr, bf, newdup2,
needlogp);
}
}
}
*needscanp = needscan;
}
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