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- // 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"
- /*
- * 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 */
- xfs_dir2_sf_hdr_t *sfp; /* shortform structure */
- 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(dp->i_df.if_u1.if_data != NULL);
- sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
- /*
- * 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)))
- 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, &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))) {
- 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, 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))) {
- 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;
- bool isblock;
- int error;
- trace_xfs_readdir(dp);
- if (xfs_is_shutdown(dp->i_mount))
- return -EIO;
- ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
- ASSERT(xfs_isilocked(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;
- 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);
- error = xfs_dir2_isblock(&args, &isblock);
- if (error)
- goto out_unlock;
- if (isblock) {
- error = xfs_dir2_block_getdents(&args, ctx, &lock_mode);
- goto out_unlock;
- }
- error = xfs_dir2_leaf_getdents(&args, ctx, bufsize, &lock_mode);
- out_unlock:
- if (lock_mode)
- xfs_iunlock(dp, lock_mode);
- return error;
- }
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