// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* Copyright (c) 2013 Red Hat, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_trace.h"
#include "xfs_bmap.h"
#include "xfs_trans.h"
#include "xfs_error.h"
#include "xfs_health.h"
/*
* Directory file type support functions
*/
static unsigned char xfs_dir3_filetype_table[] = {
DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK,
DT_FIFO, DT_SOCK, DT_LNK, DT_WHT,
};
unsigned char
xfs_dir3_get_dtype(
struct xfs_mount *mp,
uint8_t filetype)
{
if (!xfs_has_ftype(mp))
return DT_UNKNOWN;
if (filetype >= XFS_DIR3_FT_MAX)
return DT_UNKNOWN;
return xfs_dir3_filetype_table[filetype];
}
STATIC int
xfs_dir2_sf_getdents(
struct xfs_da_args *args,
struct dir_context *ctx)
{
int i; /* shortform entry number */
struct xfs_inode *dp = args->dp; /* incore directory inode */
struct xfs_mount *mp = dp->i_mount;
xfs_dir2_dataptr_t off; /* current entry's offset */
xfs_dir2_sf_entry_t *sfep; /* shortform directory entry */
struct xfs_dir2_sf_hdr *sfp = dp->i_df.if_data;
xfs_dir2_dataptr_t dot_offset;
xfs_dir2_dataptr_t dotdot_offset;
xfs_ino_t ino;
struct xfs_da_geometry *geo = args->geo;
ASSERT(dp->i_df.if_format == XFS_DINODE_FMT_LOCAL);
ASSERT(dp->i_df.if_bytes == dp->i_disk_size);
ASSERT(sfp != NULL);
/*
* If the block number in the offset is out of range, we're done.
*/
if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
return 0;
/*
* Precalculate offsets for "." and ".." as we will always need them.
* This relies on the fact that directories always start with the
* entries for "." and "..".
*/
dot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
geo->data_entry_offset);
dotdot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
geo->data_entry_offset +
xfs_dir2_data_entsize(mp, sizeof(".") - 1));
/*
* Put . entry unless we're starting past it.
*/
if (ctx->pos <= dot_offset) {
ctx->pos = dot_offset & 0x7fffffff;
if (!dir_emit(ctx, ".", 1, dp->i_ino, DT_DIR))
return 0;
}
/*
* Put .. entry unless we're starting past it.
*/
if (ctx->pos <= dotdot_offset) {
ino = xfs_dir2_sf_get_parent_ino(sfp);
ctx->pos = dotdot_offset & 0x7fffffff;
if (!dir_emit(ctx, "..", 2, ino, DT_DIR))
return 0;
}
/*
* Loop while there are more entries and put'ing works.
*/
sfep = xfs_dir2_sf_firstentry(sfp);
for (i = 0; i < sfp->count; i++) {
uint8_t filetype;
off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
xfs_dir2_sf_get_offset(sfep));
if (ctx->pos > off) {
sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep);
continue;
}
ino = xfs_dir2_sf_get_ino(mp, sfp, sfep);
filetype = xfs_dir2_sf_get_ftype(mp, sfep);
ctx->pos = off & 0x7fffffff;
if (XFS_IS_CORRUPT(dp->i_mount,
!xfs_dir2_namecheck(sfep->name,
sfep->namelen))) {
xfs_dirattr_mark_sick(dp, XFS_DATA_FORK);
return -EFSCORRUPTED;
}
if (!dir_emit(ctx, (char *)sfep->name, sfep->namelen, ino,
xfs_dir3_get_dtype(mp, filetype)))
return 0;
sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep);
}
ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &
0x7fffffff;
return 0;
}
/*
* Readdir for block directories.
*/
STATIC int
xfs_dir2_block_getdents(
struct xfs_da_args *args,
struct dir_context *ctx,
unsigned int *lock_mode)
{
struct xfs_inode *dp = args->dp; /* incore directory inode */
struct xfs_buf *bp; /* buffer for block */
int error; /* error return value */
int wantoff; /* starting block offset */
xfs_off_t cook;
struct xfs_da_geometry *geo = args->geo;
unsigned int offset, next_offset;
unsigned int end;
/*
* If the block number in the offset is out of range, we're done.
*/
if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)
return 0;
error = xfs_dir3_block_read(args->trans, dp, args->owner, &bp);
if (error)
return error;
xfs_iunlock(dp, *lock_mode);
*lock_mode = 0;
/*
* Extract the byte offset we start at from the seek pointer.
* We'll skip entries before this.
*/
wantoff = xfs_dir2_dataptr_to_off(geo, ctx->pos);
xfs_dir3_data_check(dp, bp);
/*
* Loop over the data portion of the block.
* Each object is a real entry (dep) or an unused one (dup).
*/
end = xfs_dir3_data_end_offset(geo, bp->b_addr);
for (offset = geo->data_entry_offset;
offset < end;
offset = next_offset) {
struct xfs_dir2_data_unused *dup = bp->b_addr + offset;
struct xfs_dir2_data_entry *dep = bp->b_addr + offset;
uint8_t filetype;
/*
* Unused, skip it.
*/
if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
next_offset = offset + be16_to_cpu(dup->length);
continue;
}
/*
* Bump pointer for the next iteration.
*/
next_offset = offset +
xfs_dir2_data_entsize(dp->i_mount, dep->namelen);
/*
* The entry is before the desired starting point, skip it.
*/
if (offset < wantoff)
continue;
cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, offset);
ctx->pos = cook & 0x7fffffff;
filetype = xfs_dir2_data_get_ftype(dp->i_mount, dep);
/*
* If it didn't fit, set the final offset to here & return.
*/
if (XFS_IS_CORRUPT(dp->i_mount,
!xfs_dir2_namecheck(dep->name,
dep->namelen))) {
xfs_dirattr_mark_sick(dp, XFS_DATA_FORK);
error = -EFSCORRUPTED;
goto out_rele;
}
if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
be64_to_cpu(dep->inumber),
xfs_dir3_get_dtype(dp->i_mount, filetype)))
goto out_rele;
}
/*
* Reached the end of the block.
* Set the offset to a non-existent block 1 and return.
*/
ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &
0x7fffffff;
out_rele:
xfs_trans_brelse(args->trans, bp);
return error;
}
/*
* Read a directory block and initiate readahead for blocks beyond that.
* We maintain a sliding readahead window of the remaining space in the
* buffer rounded up to the nearest block.
*/
STATIC int
xfs_dir2_leaf_readbuf(
struct xfs_da_args *args,
size_t bufsize,
xfs_dir2_off_t *cur_off,
xfs_dablk_t *ra_blk,
struct xfs_buf **bpp)
{
struct xfs_inode *dp = args->dp;
struct xfs_buf *bp = NULL;
struct xfs_da_geometry *geo = args->geo;
struct xfs_ifork *ifp = xfs_ifork_ptr(dp, XFS_DATA_FORK);
struct xfs_bmbt_irec map;
struct blk_plug plug;
xfs_dir2_off_t new_off;
xfs_dablk_t next_ra;
xfs_dablk_t map_off;
xfs_dablk_t last_da;
struct xfs_iext_cursor icur;
int ra_want;
int error = 0;
error = xfs_iread_extents(args->trans, dp, XFS_DATA_FORK);
if (error)
goto out;
/*
* Look for mapped directory blocks at or above the current offset.
* Truncate down to the nearest directory block to start the scanning
* operation.
*/
last_da = xfs_dir2_byte_to_da(geo, XFS_DIR2_LEAF_OFFSET);
map_off = xfs_dir2_db_to_da(geo, xfs_dir2_byte_to_db(geo, *cur_off));
if (!xfs_iext_lookup_extent(dp, ifp, map_off, &icur, &map))
goto out;
if (map.br_startoff >= last_da)
goto out;
xfs_trim_extent(&map, map_off, last_da - map_off);
/* Read the directory block of that first mapping. */
new_off = xfs_dir2_da_to_byte(geo, map.br_startoff);
if (new_off > *cur_off)
*cur_off = new_off;
error = xfs_dir3_data_read(args->trans, dp, args->owner,
map.br_startoff, 0, &bp);
if (error)
goto out;
/*
* Start readahead for the next bufsize's worth of dir data blocks.
* We may have already issued readahead for some of that range;
* ra_blk tracks the last block we tried to read(ahead).
*/
ra_want = howmany(bufsize + geo->blksize, (1 << geo->fsblog));
if (*ra_blk >= last_da)
goto out;
else if (*ra_blk == 0)
*ra_blk = map.br_startoff;
next_ra = map.br_startoff + geo->fsbcount;
if (next_ra >= last_da)
goto out_no_ra;
if (map.br_blockcount < geo->fsbcount &&
!xfs_iext_next_extent(ifp, &icur, &map))
goto out_no_ra;
if (map.br_startoff >= last_da)
goto out_no_ra;
xfs_trim_extent(&map, next_ra, last_da - next_ra);
/* Start ra for each dir (not fs) block that has a mapping. */
blk_start_plug(&plug);
while (ra_want > 0) {
next_ra = roundup((xfs_dablk_t)map.br_startoff, geo->fsbcount);
while (ra_want > 0 &&
next_ra < map.br_startoff + map.br_blockcount) {
if (next_ra >= last_da) {
*ra_blk = last_da;
break;
}
if (next_ra > *ra_blk) {
xfs_dir3_data_readahead(dp, next_ra,
XFS_DABUF_MAP_HOLE_OK);
*ra_blk = next_ra;
}
ra_want -= geo->fsbcount;
next_ra += geo->fsbcount;
}
if (!xfs_iext_next_extent(ifp, &icur, &map)) {
*ra_blk = last_da;
break;
}
}
blk_finish_plug(&plug);
out:
*bpp = bp;
return error;
out_no_ra:
*ra_blk = last_da;
goto out;
}
/*
* Getdents (readdir) for leaf and node directories.
* This reads the data blocks only, so is the same for both forms.
*/
STATIC int
xfs_dir2_leaf_getdents(
struct xfs_da_args *args,
struct dir_context *ctx,
size_t bufsize,
unsigned int *lock_mode)
{
struct xfs_inode *dp = args->dp;
struct xfs_mount *mp = dp->i_mount;
struct xfs_buf *bp = NULL; /* data block buffer */
xfs_dir2_data_entry_t *dep; /* data entry */
xfs_dir2_data_unused_t *dup; /* unused entry */
struct xfs_da_geometry *geo = args->geo;
xfs_dablk_t rablk = 0; /* current readahead block */
xfs_dir2_off_t curoff; /* current overall offset */
int length; /* temporary length value */
int byteoff; /* offset in current block */
unsigned int offset = 0;
int error = 0; /* error return value */
/*
* If the offset is at or past the largest allowed value,
* give up right away.
*/
if (ctx->pos >= XFS_DIR2_MAX_DATAPTR)
return 0;
/*
* Inside the loop we keep the main offset value as a byte offset
* in the directory file.
*/
curoff = xfs_dir2_dataptr_to_byte(ctx->pos);
/*
* Loop over directory entries until we reach the end offset.
* Get more blocks and readahead as necessary.
*/
while (curoff < XFS_DIR2_LEAF_OFFSET) {
uint8_t filetype;
/*
* If we have no buffer, or we're off the end of the
* current buffer, need to get another one.
*/
if (!bp || offset >= geo->blksize) {
if (bp) {
xfs_trans_brelse(args->trans, bp);
bp = NULL;
}
if (*lock_mode == 0)
*lock_mode = xfs_ilock_data_map_shared(dp);
error = xfs_dir2_leaf_readbuf(args, bufsize, &curoff,
&rablk, &bp);
if (error || !bp)
break;
xfs_iunlock(dp, *lock_mode);
*lock_mode = 0;
xfs_dir3_data_check(dp, bp);
/*
* Find our position in the block.
*/
offset = geo->data_entry_offset;
byteoff = xfs_dir2_byte_to_off(geo, curoff);
/*
* Skip past the header.
*/
if (byteoff == 0)
curoff += geo->data_entry_offset;
/*
* Skip past entries until we reach our offset.
*/
else {
while (offset < byteoff) {
dup = bp->b_addr + offset;
if (be16_to_cpu(dup->freetag)
== XFS_DIR2_DATA_FREE_TAG) {
length = be16_to_cpu(dup->length);
offset += length;
continue;
}
dep = bp->b_addr + offset;
length = xfs_dir2_data_entsize(mp,
dep->namelen);
offset += length;
}
/*
* Now set our real offset.
*/
curoff =
xfs_dir2_db_off_to_byte(geo,
xfs_dir2_byte_to_db(geo, curoff),
offset);
if (offset >= geo->blksize)
continue;
}
}
/*
* We have a pointer to an entry. Is it a live one?
*/
dup = bp->b_addr + offset;
/*
* No, it's unused, skip over it.
*/
if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
length = be16_to_cpu(dup->length);
offset += length;
curoff += length;
continue;
}
dep = bp->b_addr + offset;
length = xfs_dir2_data_entsize(mp, dep->namelen);
filetype = xfs_dir2_data_get_ftype(mp, dep);
ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
if (XFS_IS_CORRUPT(dp->i_mount,
!xfs_dir2_namecheck(dep->name,
dep->namelen))) {
xfs_dirattr_mark_sick(dp, XFS_DATA_FORK);
error = -EFSCORRUPTED;
break;
}
if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
be64_to_cpu(dep->inumber),
xfs_dir3_get_dtype(dp->i_mount, filetype)))
break;
/*
* Advance to next entry in the block.
*/
offset += length;
curoff += length;
/* bufsize may have just been a guess; don't go negative */
bufsize = bufsize > length ? bufsize - length : 0;
}
/*
* All done. Set output offset value to current offset.
*/
if (curoff > xfs_dir2_dataptr_to_byte(XFS_DIR2_MAX_DATAPTR))
ctx->pos = XFS_DIR2_MAX_DATAPTR & 0x7fffffff;
else
ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
if (bp)
xfs_trans_brelse(args->trans, bp);
return error;
}
/*
* Read a directory.
*
* If supplied, the transaction collects locked dir buffers to avoid
* nested buffer deadlocks. This function does not dirty the
* transaction. The caller must hold the IOLOCK (shared or exclusive)
* before calling this function.
*/
int
xfs_readdir(
struct xfs_trans *tp,
struct xfs_inode *dp,
struct dir_context *ctx,
size_t bufsize)
{
struct xfs_da_args args = { NULL };
unsigned int lock_mode;
int error;
trace_xfs_readdir(dp);
if (xfs_is_shutdown(dp->i_mount))
return -EIO;
if (xfs_ifork_zapped(dp, XFS_DATA_FORK))
return -EIO;
ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
xfs_assert_ilocked(dp, XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL);
XFS_STATS_INC(dp->i_mount, xs_dir_getdents);
args.dp = dp;
args.geo = dp->i_mount->m_dir_geo;
args.trans = tp;
args.owner = dp->i_ino;
if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL)
return xfs_dir2_sf_getdents(&args, ctx);
lock_mode = xfs_ilock_data_map_shared(dp);
switch (xfs_dir2_format(&args, &error)) {
case XFS_DIR2_FMT_BLOCK:
error = xfs_dir2_block_getdents(&args, ctx, &lock_mode);
break;
case XFS_DIR2_FMT_LEAF:
case XFS_DIR2_FMT_NODE:
error = xfs_dir2_leaf_getdents(&args, ctx, bufsize, &lock_mode);
break;
default:
break;
}
if (lock_mode)
xfs_iunlock(dp, lock_mode);
return error;
}
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