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550 lines
14 KiB
550 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (c) 2000-2005 Silicon Graphics, Inc. |
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* Copyright (c) 2013 Red Hat, Inc. |
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* All Rights Reserved. |
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*/ |
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#include "xfs.h" |
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#include "xfs_fs.h" |
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#include "xfs_shared.h" |
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#include "xfs_format.h" |
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#include "xfs_log_format.h" |
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#include "xfs_trans_resv.h" |
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#include "xfs_mount.h" |
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#include "xfs_inode.h" |
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#include "xfs_dir2.h" |
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#include "xfs_dir2_priv.h" |
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#include "xfs_trace.h" |
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#include "xfs_bmap.h" |
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#include "xfs_trans.h" |
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#include "xfs_error.h" |
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|
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/* |
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* Directory file type support functions |
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*/ |
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static unsigned char xfs_dir3_filetype_table[] = { |
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DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, |
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DT_FIFO, DT_SOCK, DT_LNK, DT_WHT, |
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}; |
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unsigned char |
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xfs_dir3_get_dtype( |
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struct xfs_mount *mp, |
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uint8_t filetype) |
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{ |
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if (!xfs_has_ftype(mp)) |
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return DT_UNKNOWN; |
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|
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if (filetype >= XFS_DIR3_FT_MAX) |
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return DT_UNKNOWN; |
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|
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return xfs_dir3_filetype_table[filetype]; |
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} |
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STATIC int |
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xfs_dir2_sf_getdents( |
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struct xfs_da_args *args, |
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struct dir_context *ctx) |
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{ |
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int i; /* shortform entry number */ |
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struct xfs_inode *dp = args->dp; /* incore directory inode */ |
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struct xfs_mount *mp = dp->i_mount; |
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xfs_dir2_dataptr_t off; /* current entry's offset */ |
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xfs_dir2_sf_entry_t *sfep; /* shortform directory entry */ |
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xfs_dir2_sf_hdr_t *sfp; /* shortform structure */ |
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xfs_dir2_dataptr_t dot_offset; |
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xfs_dir2_dataptr_t dotdot_offset; |
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xfs_ino_t ino; |
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struct xfs_da_geometry *geo = args->geo; |
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ASSERT(dp->i_df.if_format == XFS_DINODE_FMT_LOCAL); |
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ASSERT(dp->i_df.if_bytes == dp->i_disk_size); |
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ASSERT(dp->i_df.if_u1.if_data != NULL); |
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sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data; |
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/* |
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* If the block number in the offset is out of range, we're done. |
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*/ |
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if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk) |
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return 0; |
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|
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/* |
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* Precalculate offsets for "." and ".." as we will always need them. |
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* This relies on the fact that directories always start with the |
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* entries for "." and "..". |
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*/ |
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dot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, |
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geo->data_entry_offset); |
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dotdot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, |
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geo->data_entry_offset + |
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xfs_dir2_data_entsize(mp, sizeof(".") - 1)); |
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|
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/* |
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* Put . entry unless we're starting past it. |
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*/ |
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if (ctx->pos <= dot_offset) { |
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ctx->pos = dot_offset & 0x7fffffff; |
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if (!dir_emit(ctx, ".", 1, dp->i_ino, DT_DIR)) |
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return 0; |
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} |
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/* |
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* Put .. entry unless we're starting past it. |
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*/ |
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if (ctx->pos <= dotdot_offset) { |
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ino = xfs_dir2_sf_get_parent_ino(sfp); |
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ctx->pos = dotdot_offset & 0x7fffffff; |
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if (!dir_emit(ctx, "..", 2, ino, DT_DIR)) |
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return 0; |
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} |
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/* |
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* Loop while there are more entries and put'ing works. |
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*/ |
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sfep = xfs_dir2_sf_firstentry(sfp); |
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for (i = 0; i < sfp->count; i++) { |
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uint8_t filetype; |
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off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, |
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xfs_dir2_sf_get_offset(sfep)); |
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if (ctx->pos > off) { |
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sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep); |
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continue; |
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} |
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ino = xfs_dir2_sf_get_ino(mp, sfp, sfep); |
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filetype = xfs_dir2_sf_get_ftype(mp, sfep); |
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ctx->pos = off & 0x7fffffff; |
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if (XFS_IS_CORRUPT(dp->i_mount, |
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!xfs_dir2_namecheck(sfep->name, |
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sfep->namelen))) |
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return -EFSCORRUPTED; |
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if (!dir_emit(ctx, (char *)sfep->name, sfep->namelen, ino, |
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xfs_dir3_get_dtype(mp, filetype))) |
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return 0; |
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sfep = xfs_dir2_sf_nextentry(mp, sfp, sfep); |
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} |
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ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) & |
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0x7fffffff; |
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return 0; |
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} |
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/* |
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* Readdir for block directories. |
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*/ |
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STATIC int |
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xfs_dir2_block_getdents( |
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struct xfs_da_args *args, |
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struct dir_context *ctx, |
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unsigned int *lock_mode) |
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{ |
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struct xfs_inode *dp = args->dp; /* incore directory inode */ |
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struct xfs_buf *bp; /* buffer for block */ |
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int error; /* error return value */ |
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int wantoff; /* starting block offset */ |
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xfs_off_t cook; |
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struct xfs_da_geometry *geo = args->geo; |
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unsigned int offset, next_offset; |
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unsigned int end; |
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|
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/* |
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* If the block number in the offset is out of range, we're done. |
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*/ |
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if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk) |
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return 0; |
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error = xfs_dir3_block_read(args->trans, dp, &bp); |
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if (error) |
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return error; |
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xfs_iunlock(dp, *lock_mode); |
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*lock_mode = 0; |
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/* |
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* Extract the byte offset we start at from the seek pointer. |
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* We'll skip entries before this. |
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*/ |
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wantoff = xfs_dir2_dataptr_to_off(geo, ctx->pos); |
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xfs_dir3_data_check(dp, bp); |
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/* |
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* Loop over the data portion of the block. |
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* Each object is a real entry (dep) or an unused one (dup). |
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*/ |
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end = xfs_dir3_data_end_offset(geo, bp->b_addr); |
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for (offset = geo->data_entry_offset; |
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offset < end; |
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offset = next_offset) { |
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struct xfs_dir2_data_unused *dup = bp->b_addr + offset; |
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struct xfs_dir2_data_entry *dep = bp->b_addr + offset; |
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uint8_t filetype; |
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/* |
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* Unused, skip it. |
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*/ |
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if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) { |
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next_offset = offset + be16_to_cpu(dup->length); |
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continue; |
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} |
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/* |
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* Bump pointer for the next iteration. |
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*/ |
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next_offset = offset + |
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xfs_dir2_data_entsize(dp->i_mount, dep->namelen); |
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/* |
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* The entry is before the desired starting point, skip it. |
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*/ |
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if (offset < wantoff) |
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continue; |
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cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk, offset); |
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ctx->pos = cook & 0x7fffffff; |
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filetype = xfs_dir2_data_get_ftype(dp->i_mount, dep); |
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/* |
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* If it didn't fit, set the final offset to here & return. |
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*/ |
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if (XFS_IS_CORRUPT(dp->i_mount, |
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!xfs_dir2_namecheck(dep->name, |
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dep->namelen))) { |
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error = -EFSCORRUPTED; |
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goto out_rele; |
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} |
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if (!dir_emit(ctx, (char *)dep->name, dep->namelen, |
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be64_to_cpu(dep->inumber), |
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xfs_dir3_get_dtype(dp->i_mount, filetype))) |
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goto out_rele; |
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} |
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/* |
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* Reached the end of the block. |
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* Set the offset to a non-existent block 1 and return. |
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*/ |
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ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) & |
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0x7fffffff; |
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out_rele: |
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xfs_trans_brelse(args->trans, bp); |
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return error; |
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} |
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/* |
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* Read a directory block and initiate readahead for blocks beyond that. |
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* We maintain a sliding readahead window of the remaining space in the |
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* buffer rounded up to the nearest block. |
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*/ |
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STATIC int |
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xfs_dir2_leaf_readbuf( |
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struct xfs_da_args *args, |
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size_t bufsize, |
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xfs_dir2_off_t *cur_off, |
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xfs_dablk_t *ra_blk, |
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struct xfs_buf **bpp) |
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{ |
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struct xfs_inode *dp = args->dp; |
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struct xfs_buf *bp = NULL; |
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struct xfs_da_geometry *geo = args->geo; |
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struct xfs_ifork *ifp = xfs_ifork_ptr(dp, XFS_DATA_FORK); |
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struct xfs_bmbt_irec map; |
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struct blk_plug plug; |
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xfs_dir2_off_t new_off; |
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xfs_dablk_t next_ra; |
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xfs_dablk_t map_off; |
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xfs_dablk_t last_da; |
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struct xfs_iext_cursor icur; |
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int ra_want; |
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int error = 0; |
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error = xfs_iread_extents(args->trans, dp, XFS_DATA_FORK); |
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if (error) |
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goto out; |
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/* |
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* Look for mapped directory blocks at or above the current offset. |
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* Truncate down to the nearest directory block to start the scanning |
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* operation. |
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*/ |
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last_da = xfs_dir2_byte_to_da(geo, XFS_DIR2_LEAF_OFFSET); |
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map_off = xfs_dir2_db_to_da(geo, xfs_dir2_byte_to_db(geo, *cur_off)); |
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if (!xfs_iext_lookup_extent(dp, ifp, map_off, &icur, &map)) |
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goto out; |
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if (map.br_startoff >= last_da) |
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goto out; |
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xfs_trim_extent(&map, map_off, last_da - map_off); |
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/* Read the directory block of that first mapping. */ |
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new_off = xfs_dir2_da_to_byte(geo, map.br_startoff); |
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if (new_off > *cur_off) |
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*cur_off = new_off; |
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error = xfs_dir3_data_read(args->trans, dp, map.br_startoff, 0, &bp); |
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if (error) |
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goto out; |
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/* |
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* Start readahead for the next bufsize's worth of dir data blocks. |
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* We may have already issued readahead for some of that range; |
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* ra_blk tracks the last block we tried to read(ahead). |
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*/ |
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ra_want = howmany(bufsize + geo->blksize, (1 << geo->fsblog)); |
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if (*ra_blk >= last_da) |
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goto out; |
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else if (*ra_blk == 0) |
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*ra_blk = map.br_startoff; |
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next_ra = map.br_startoff + geo->fsbcount; |
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if (next_ra >= last_da) |
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goto out_no_ra; |
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if (map.br_blockcount < geo->fsbcount && |
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!xfs_iext_next_extent(ifp, &icur, &map)) |
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goto out_no_ra; |
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if (map.br_startoff >= last_da) |
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goto out_no_ra; |
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xfs_trim_extent(&map, next_ra, last_da - next_ra); |
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/* Start ra for each dir (not fs) block that has a mapping. */ |
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blk_start_plug(&plug); |
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while (ra_want > 0) { |
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next_ra = roundup((xfs_dablk_t)map.br_startoff, geo->fsbcount); |
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while (ra_want > 0 && |
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next_ra < map.br_startoff + map.br_blockcount) { |
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if (next_ra >= last_da) { |
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*ra_blk = last_da; |
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break; |
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} |
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if (next_ra > *ra_blk) { |
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xfs_dir3_data_readahead(dp, next_ra, |
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XFS_DABUF_MAP_HOLE_OK); |
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*ra_blk = next_ra; |
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} |
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ra_want -= geo->fsbcount; |
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next_ra += geo->fsbcount; |
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} |
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if (!xfs_iext_next_extent(ifp, &icur, &map)) { |
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*ra_blk = last_da; |
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break; |
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} |
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} |
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blk_finish_plug(&plug); |
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out: |
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*bpp = bp; |
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return error; |
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out_no_ra: |
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*ra_blk = last_da; |
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goto out; |
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} |
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/* |
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* Getdents (readdir) for leaf and node directories. |
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* This reads the data blocks only, so is the same for both forms. |
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*/ |
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STATIC int |
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xfs_dir2_leaf_getdents( |
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struct xfs_da_args *args, |
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struct dir_context *ctx, |
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size_t bufsize, |
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unsigned int *lock_mode) |
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{ |
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struct xfs_inode *dp = args->dp; |
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struct xfs_mount *mp = dp->i_mount; |
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struct xfs_buf *bp = NULL; /* data block buffer */ |
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xfs_dir2_data_entry_t *dep; /* data entry */ |
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xfs_dir2_data_unused_t *dup; /* unused entry */ |
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struct xfs_da_geometry *geo = args->geo; |
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xfs_dablk_t rablk = 0; /* current readahead block */ |
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xfs_dir2_off_t curoff; /* current overall offset */ |
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int length; /* temporary length value */ |
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int byteoff; /* offset in current block */ |
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unsigned int offset = 0; |
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int error = 0; /* error return value */ |
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|
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/* |
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* If the offset is at or past the largest allowed value, |
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* give up right away. |
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*/ |
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if (ctx->pos >= XFS_DIR2_MAX_DATAPTR) |
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return 0; |
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|
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/* |
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* Inside the loop we keep the main offset value as a byte offset |
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* in the directory file. |
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*/ |
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curoff = xfs_dir2_dataptr_to_byte(ctx->pos); |
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|
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/* |
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* Loop over directory entries until we reach the end offset. |
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* Get more blocks and readahead as necessary. |
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*/ |
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while (curoff < XFS_DIR2_LEAF_OFFSET) { |
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uint8_t filetype; |
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/* |
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* If we have no buffer, or we're off the end of the |
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* current buffer, need to get another one. |
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*/ |
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if (!bp || offset >= geo->blksize) { |
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if (bp) { |
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xfs_trans_brelse(args->trans, bp); |
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bp = NULL; |
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} |
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|
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if (*lock_mode == 0) |
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*lock_mode = xfs_ilock_data_map_shared(dp); |
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error = xfs_dir2_leaf_readbuf(args, bufsize, &curoff, |
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&rablk, &bp); |
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if (error || !bp) |
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break; |
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xfs_iunlock(dp, *lock_mode); |
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*lock_mode = 0; |
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xfs_dir3_data_check(dp, bp); |
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/* |
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* Find our position in the block. |
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*/ |
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offset = geo->data_entry_offset; |
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byteoff = xfs_dir2_byte_to_off(geo, curoff); |
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/* |
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* Skip past the header. |
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*/ |
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if (byteoff == 0) |
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curoff += geo->data_entry_offset; |
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/* |
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* Skip past entries until we reach our offset. |
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*/ |
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else { |
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while (offset < byteoff) { |
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dup = bp->b_addr + offset; |
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|
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if (be16_to_cpu(dup->freetag) |
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== XFS_DIR2_DATA_FREE_TAG) { |
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|
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length = be16_to_cpu(dup->length); |
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offset += length; |
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continue; |
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} |
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dep = bp->b_addr + offset; |
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length = xfs_dir2_data_entsize(mp, |
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dep->namelen); |
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offset += length; |
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} |
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/* |
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* Now set our real offset. |
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*/ |
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curoff = |
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xfs_dir2_db_off_to_byte(geo, |
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xfs_dir2_byte_to_db(geo, curoff), |
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offset); |
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if (offset >= geo->blksize) |
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continue; |
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} |
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} |
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|
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/* |
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* We have a pointer to an entry. Is it a live one? |
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*/ |
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dup = bp->b_addr + offset; |
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|
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/* |
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* No, it's unused, skip over it. |
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*/ |
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if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) { |
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length = be16_to_cpu(dup->length); |
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offset += length; |
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curoff += length; |
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continue; |
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} |
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|
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dep = bp->b_addr + offset; |
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length = xfs_dir2_data_entsize(mp, dep->namelen); |
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filetype = xfs_dir2_data_get_ftype(mp, dep); |
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|
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ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff; |
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if (XFS_IS_CORRUPT(dp->i_mount, |
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!xfs_dir2_namecheck(dep->name, |
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dep->namelen))) { |
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error = -EFSCORRUPTED; |
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break; |
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} |
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if (!dir_emit(ctx, (char *)dep->name, dep->namelen, |
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be64_to_cpu(dep->inumber), |
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xfs_dir3_get_dtype(dp->i_mount, filetype))) |
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break; |
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|
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/* |
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* Advance to next entry in the block. |
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*/ |
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offset += length; |
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curoff += length; |
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/* bufsize may have just been a guess; don't go negative */ |
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bufsize = bufsize > length ? bufsize - length : 0; |
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} |
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|
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/* |
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* All done. Set output offset value to current offset. |
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*/ |
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if (curoff > xfs_dir2_dataptr_to_byte(XFS_DIR2_MAX_DATAPTR)) |
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ctx->pos = XFS_DIR2_MAX_DATAPTR & 0x7fffffff; |
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else |
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ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff; |
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if (bp) |
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xfs_trans_brelse(args->trans, bp); |
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return error; |
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} |
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|
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/* |
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* Read a directory. |
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* |
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* If supplied, the transaction collects locked dir buffers to avoid |
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* nested buffer deadlocks. This function does not dirty the |
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* transaction. The caller must hold the IOLOCK (shared or exclusive) |
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* before calling this function. |
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*/ |
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int |
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xfs_readdir( |
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struct xfs_trans *tp, |
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struct xfs_inode *dp, |
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struct dir_context *ctx, |
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size_t bufsize) |
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{ |
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struct xfs_da_args args = { NULL }; |
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unsigned int lock_mode; |
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bool isblock; |
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int error; |
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|
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trace_xfs_readdir(dp); |
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|
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if (xfs_is_shutdown(dp->i_mount)) |
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return -EIO; |
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|
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ASSERT(S_ISDIR(VFS_I(dp)->i_mode)); |
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ASSERT(xfs_isilocked(dp, XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)); |
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XFS_STATS_INC(dp->i_mount, xs_dir_getdents); |
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|
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args.dp = dp; |
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args.geo = dp->i_mount->m_dir_geo; |
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args.trans = tp; |
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|
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if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL) |
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return xfs_dir2_sf_getdents(&args, ctx); |
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|
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lock_mode = xfs_ilock_data_map_shared(dp); |
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error = xfs_dir2_isblock(&args, &isblock); |
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if (error) |
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goto out_unlock; |
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|
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if (isblock) { |
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error = xfs_dir2_block_getdents(&args, ctx, &lock_mode); |
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goto out_unlock; |
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} |
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|
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error = xfs_dir2_leaf_getdents(&args, ctx, bufsize, &lock_mode); |
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|
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out_unlock: |
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if (lock_mode) |
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xfs_iunlock(dp, lock_mode); |
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return error; |
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}
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