v4.19.13 snapshot.
diff --git a/fs/xfs/xfs_dir2_readdir.c b/fs/xfs/xfs_dir2_readdir.c
new file mode 100644
index 0000000..5142e64
--- /dev/null
+++ b/fs/xfs/xfs_dir2_readdir.c
@@ -0,0 +1,529 @@
+// 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_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.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_trace.h"
+#include "xfs_bmap.h"
+#include "xfs_trans.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_sb_version_hasftype(&mp->m_sb))
+ 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 */
+ 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_flags & XFS_IFINLINE);
+ ASSERT(dp->i_df.if_bytes == dp->i_d.di_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.
+ *
+ * XXX(hch): the second argument is sometimes 0 and sometimes
+ * geo->datablk
+ */
+ dot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
+ dp->d_ops->data_dot_offset);
+ dotdot_offset = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
+ dp->d_ops->data_dotdot_offset);
+
+ /*
+ * 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 = dp->d_ops->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 = dp->d_ops->sf_nextentry(sfp, sfep);
+ continue;
+ }
+
+ ino = dp->d_ops->sf_get_ino(sfp, sfep);
+ filetype = dp->d_ops->sf_get_ftype(sfep);
+ ctx->pos = off & 0x7fffffff;
+ if (!dir_emit(ctx, (char *)sfep->name, sfep->namelen, ino,
+ xfs_dir3_get_dtype(dp->i_mount, filetype)))
+ return 0;
+ sfep = dp->d_ops->sf_nextentry(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)
+{
+ struct xfs_inode *dp = args->dp; /* incore directory inode */
+ xfs_dir2_data_hdr_t *hdr; /* block header */
+ struct xfs_buf *bp; /* buffer for block */
+ xfs_dir2_data_entry_t *dep; /* block data entry */
+ xfs_dir2_data_unused_t *dup; /* block unused entry */
+ char *endptr; /* end of the data entries */
+ int error; /* error return value */
+ char *ptr; /* current data entry */
+ int wantoff; /* starting block offset */
+ xfs_off_t cook;
+ struct xfs_da_geometry *geo = args->geo;
+ int lock_mode;
+
+ /*
+ * 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;
+
+ lock_mode = xfs_ilock_data_map_shared(dp);
+ error = xfs_dir3_block_read(args->trans, dp, &bp);
+ xfs_iunlock(dp, lock_mode);
+ if (error)
+ return error;
+
+ /*
+ * 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);
+ hdr = bp->b_addr;
+ xfs_dir3_data_check(dp, bp);
+ /*
+ * Set up values for the loop.
+ */
+ ptr = (char *)dp->d_ops->data_entry_p(hdr);
+ endptr = xfs_dir3_data_endp(geo, hdr);
+
+ /*
+ * Loop over the data portion of the block.
+ * Each object is a real entry (dep) or an unused one (dup).
+ */
+ while (ptr < endptr) {
+ uint8_t filetype;
+
+ dup = (xfs_dir2_data_unused_t *)ptr;
+ /*
+ * Unused, skip it.
+ */
+ if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
+ ptr += be16_to_cpu(dup->length);
+ continue;
+ }
+
+ dep = (xfs_dir2_data_entry_t *)ptr;
+
+ /*
+ * Bump pointer for the next iteration.
+ */
+ ptr += dp->d_ops->data_entsize(dep->namelen);
+ /*
+ * The entry is before the desired starting point, skip it.
+ */
+ if ((char *)dep - (char *)hdr < wantoff)
+ continue;
+
+ cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
+ (char *)dep - (char *)hdr);
+
+ ctx->pos = cook & 0x7fffffff;
+ filetype = dp->d_ops->data_get_ftype(dep);
+ /*
+ * If it didn't fit, set the final offset to here & return.
+ */
+ if (!dir_emit(ctx, (char *)dep->name, dep->namelen,
+ be64_to_cpu(dep->inumber),
+ xfs_dir3_get_dtype(dp->i_mount, filetype))) {
+ xfs_trans_brelse(args->trans, bp);
+ return 0;
+ }
+ }
+
+ /*
+ * 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;
+ xfs_trans_brelse(args->trans, bp);
+ return 0;
+}
+
+/*
+ * 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;
+
+ if (!(ifp->if_flags & XFS_IFEXTENTS)) {
+ 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, -1, &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, -2);
+ *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)
+{
+ struct xfs_inode *dp = args->dp;
+ struct xfs_buf *bp = NULL; /* data block buffer */
+ xfs_dir2_data_hdr_t *hdr; /* data block header */
+ xfs_dir2_data_entry_t *dep; /* data entry */
+ xfs_dir2_data_unused_t *dup; /* unused entry */
+ char *ptr = NULL; /* pointer to current data */
+ 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 */
+ int lock_mode;
+ 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 || ptr >= (char *)bp->b_addr + geo->blksize) {
+ if (bp) {
+ xfs_trans_brelse(args->trans, bp);
+ bp = NULL;
+ }
+
+ lock_mode = xfs_ilock_data_map_shared(dp);
+ error = xfs_dir2_leaf_readbuf(args, bufsize, &curoff,
+ &rablk, &bp);
+ xfs_iunlock(dp, lock_mode);
+ if (error || !bp)
+ break;
+
+ hdr = bp->b_addr;
+ xfs_dir3_data_check(dp, bp);
+ /*
+ * Find our position in the block.
+ */
+ ptr = (char *)dp->d_ops->data_entry_p(hdr);
+ byteoff = xfs_dir2_byte_to_off(geo, curoff);
+ /*
+ * Skip past the header.
+ */
+ if (byteoff == 0)
+ curoff += dp->d_ops->data_entry_offset;
+ /*
+ * Skip past entries until we reach our offset.
+ */
+ else {
+ while ((char *)ptr - (char *)hdr < byteoff) {
+ dup = (xfs_dir2_data_unused_t *)ptr;
+
+ if (be16_to_cpu(dup->freetag)
+ == XFS_DIR2_DATA_FREE_TAG) {
+
+ length = be16_to_cpu(dup->length);
+ ptr += length;
+ continue;
+ }
+ dep = (xfs_dir2_data_entry_t *)ptr;
+ length =
+ dp->d_ops->data_entsize(dep->namelen);
+ ptr += length;
+ }
+ /*
+ * Now set our real offset.
+ */
+ curoff =
+ xfs_dir2_db_off_to_byte(geo,
+ xfs_dir2_byte_to_db(geo, curoff),
+ (char *)ptr - (char *)hdr);
+ if (ptr >= (char *)hdr + geo->blksize) {
+ continue;
+ }
+ }
+ }
+ /*
+ * We have a pointer to an entry.
+ * Is it a live one?
+ */
+ dup = (xfs_dir2_data_unused_t *)ptr;
+ /*
+ * No, it's unused, skip over it.
+ */
+ if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
+ length = be16_to_cpu(dup->length);
+ ptr += length;
+ curoff += length;
+ continue;
+ }
+
+ dep = (xfs_dir2_data_entry_t *)ptr;
+ length = dp->d_ops->data_entsize(dep->namelen);
+ filetype = dp->d_ops->data_get_ftype(dep);
+
+ ctx->pos = xfs_dir2_byte_to_dataptr(curoff) & 0x7fffffff;
+ 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.
+ */
+ ptr += 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 should ensure that the inode is locked
+ * 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 };
+ int rval;
+ int v;
+
+ trace_xfs_readdir(dp);
+
+ if (XFS_FORCED_SHUTDOWN(dp->i_mount))
+ return -EIO;
+
+ ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
+ 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_d.di_format == XFS_DINODE_FMT_LOCAL)
+ rval = xfs_dir2_sf_getdents(&args, ctx);
+ else if ((rval = xfs_dir2_isblock(&args, &v)))
+ ;
+ else if (v)
+ rval = xfs_dir2_block_getdents(&args, ctx);
+ else
+ rval = xfs_dir2_leaf_getdents(&args, ctx, bufsize);
+
+ return rval;
+}