Merge tag 'v5.16-next-dts64' of git://git.kernel.org/pub/scm/linux/kernel/git/matthia...

[linux-2.6-microblaze.git] / fs / udf / dir.c

diff --git a/fs/udf/dir.c b/fs/udf/dir.c
index 70abdfa..42e3e55 100644 (file)
--- a/fs/udf/dir.c
+++ b/fs/udf/dir.c
@@ -31,6 +31,7 @@
 #include <linux/mm.h>
 #include <linux/slab.h>
 #include <linux/bio.h>
+#include <linux/iversion.h>
 
 #include "udf_i.h"
 #include "udf_sb.h"
@@ -43,7 +44,7 @@ static int udf_readdir(struct file *file, struct dir_context *ctx)
        struct fileIdentDesc *fi = NULL;
        struct fileIdentDesc cfi;
        udf_pblk_t block, iblock;
-       loff_t nf_pos;
+       loff_t nf_pos, emit_pos = 0;
        int flen;
        unsigned char *fname = NULL, *copy_name = NULL;
        unsigned char *nameptr;
@@ -57,6 +58,7 @@ static int udf_readdir(struct file *file, struct dir_context *ctx)
        int i, num, ret = 0;
        struct extent_position epos = { NULL, 0, {0, 0} };
        struct super_block *sb = dir->i_sb;
+       bool pos_valid = false;
 
        if (ctx->pos == 0) {
                if (!dir_emit_dot(file, ctx))
@@ -67,6 +69,21 @@ static int udf_readdir(struct file *file, struct dir_context *ctx)
        if (nf_pos >= size)
                goto out;
 
+       /*
+        * Something changed since last readdir (either lseek was called or dir
+        * changed)?  We need to verify the position correctly points at the
+        * beginning of some dir entry so that the directory parsing code does
+        * not get confused. Since UDF does not have any reliable way of
+        * identifying beginning of dir entry (names are under user control),
+        * we need to scan the directory from the beginning.
+        */
+       if (!inode_eq_iversion(dir, file->f_version)) {
+               emit_pos = nf_pos;
+               nf_pos = 0;
+       } else {
+               pos_valid = true;
+       }
+
        fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
        if (!fname) {
                ret = -ENOMEM;
@@ -122,13 +139,21 @@ static int udf_readdir(struct file *file, struct dir_context *ctx)
 
        while (nf_pos < size) {
                struct kernel_lb_addr tloc;
+               loff_t cur_pos = nf_pos;
 
-               ctx->pos = (nf_pos >> 2) + 1;
+               /* Update file position only if we got past the current one */
+               if (nf_pos >= emit_pos) {
+                       ctx->pos = (nf_pos >> 2) + 1;
+                       pos_valid = true;
+               }
 
                fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
                                        &elen, &offset);
                if (!fi)
                        goto out;
+               /* Still not at offset where user asked us to read from? */
+               if (cur_pos < emit_pos)
+                       continue;
 
                liu = le16_to_cpu(cfi.lengthOfImpUse);
                lfi = cfi.lengthFileIdent;
@@ -186,8 +211,11 @@ static int udf_readdir(struct file *file, struct dir_context *ctx)
        } /* end while */
 
        ctx->pos = (nf_pos >> 2) + 1;
+       pos_valid = true;
 
 out:
+       if (pos_valid)
+               file->f_version = inode_query_iversion(dir);
        if (fibh.sbh != fibh.ebh)
                brelse(fibh.ebh);
        brelse(fibh.sbh);