udf: cleanup directory offset handling

Position in directory returned by readdir is offset of directory entry divided
by four (don't ask me why).  Make this conversion only when reading f_pos from
userspace / writing it there and internally work in bytes.  It makes things
more easily readable and also fixes a bug (we forgot to divide length of the
entry by 4 when advancing f_pos in udf_add_entry()).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 22 deletions

diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 4bf83d570456..dacd8f4cea8a 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -160,14 +160,13 @@ static struct fileIdentDesc *udf_find_entry(struct inode *dir,
         struct extent_position epos = {};
         struct udf_inode_info *dinfo = UDF_I(dir);
 
-        size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
-        f_pos = (udf_ext0_offset(dir) >> 2);
+        size = udf_ext0_offset(dir) + dir->i_size;
+        f_pos = udf_ext0_offset(dir);
 
-        fibh->soffset = fibh->eoffset =
-                (f_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
+        fibh->soffset = fibh->eoffset = f_pos & (dir->i_sb->s_blocksize - 1);
         if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
                 fibh->sbh = fibh->ebh = NULL;
-        else if (inode_bmap(dir, f_pos >> (dir->i_sb->s_blocksize_bits - 2),
+        else if (inode_bmap(dir, f_pos >> dir->i_sb->s_blocksize_bits,
                               &epos, &eloc, &elen, &offset) ==
                                         (EXT_RECORDED_ALLOCATED >> 30)) {
                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
@@ -189,7 +188,7 @@ static struct fileIdentDesc *udf_find_entry(struct inode *dir,
                 return NULL;
         }
 
-        while ((f_pos < size)) {
+        while (f_pos < size) {
                 fi = udf_fileident_read(dir, &f_pos, fibh, cfi, &epos, &eloc,
                                         &elen, &offset);
                 if (!fi) {
@@ -342,7 +341,7 @@ static struct fileIdentDesc *udf_add_entry(struct inode *dir,
         loff_t f_pos;
         int flen;
         char *nameptr;
-        loff_t size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
+        loff_t size = udf_ext0_offset(dir) + dir->i_size;
         int nfidlen;
         uint8_t lfi;
         uint16_t liu;
@@ -370,14 +369,13 @@ static struct fileIdentDesc *udf_add_entry(struct inode *dir,
 
         nfidlen = (sizeof(struct fileIdentDesc) + namelen + 3) & ~3;
 
-        f_pos = (udf_ext0_offset(dir) >> 2);
+        f_pos = udf_ext0_offset(dir);
 
-        fibh->soffset = fibh->eoffset =
-                        (f_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
+        fibh->soffset = fibh->eoffset = f_pos & (dir->i_sb->s_blocksize - 1);
         dinfo = UDF_I(dir);
         if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
                 fibh->sbh = fibh->ebh = NULL;
-        else if (inode_bmap(dir, f_pos >> (dir->i_sb->s_blocksize_bits - 2),
+        else if (inode_bmap(dir, f_pos >> dir->i_sb->s_blocksize_bits,
                               &epos, &eloc, &elen, &offset) ==
                                         (EXT_RECORDED_ALLOCATED >> 30)) {
                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
@@ -405,7 +403,7 @@ static struct fileIdentDesc *udf_add_entry(struct inode *dir,
                 goto add;
         }
 
-        while ((f_pos < size)) {
+        while (f_pos < size) {
                 fi = udf_fileident_read(dir, &f_pos, fibh, cfi, &epos, &eloc,
                                         &elen, &offset);
 
@@ -484,7 +482,7 @@ add:
                 epos.bh = NULL;
                 fibh->soffset -= udf_ext0_offset(dir);
                 fibh->eoffset -= udf_ext0_offset(dir);
-                f_pos -= (udf_ext0_offset(dir) >> 2);
+                f_pos -= udf_ext0_offset(dir);
                 if (fibh->sbh != fibh->ebh)
                         brelse(fibh->ebh);
                 brelse(fibh->sbh);
@@ -537,8 +535,7 @@ add:
                 block = eloc.logicalBlockNum + ((elen - 1) >>
                                                 dir->i_sb->s_blocksize_bits);
                 fibh->ebh = udf_bread(dir,
-                                f_pos >> (dir->i_sb->s_blocksize_bits - 2),
-                                1, err);
+                                f_pos >> dir->i_sb->s_blocksize_bits, 1, err);
                 if (!fibh->ebh) {
                         brelse(epos.bh);
                         brelse(fibh->sbh);
@@ -775,7 +772,7 @@ static int empty_dir(struct inode *dir)
         struct fileIdentDesc *fi, cfi;
         struct udf_fileident_bh fibh;
         loff_t f_pos;
-        loff_t size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
+        loff_t size = udf_ext0_offset(dir) + dir->i_size;
         int block;
         kernel_lb_addr eloc;
         uint32_t elen;
@@ -783,14 +780,12 @@ static int empty_dir(struct inode *dir)
         struct extent_position epos = {};
         struct udf_inode_info *dinfo = UDF_I(dir);
 
-        f_pos = (udf_ext0_offset(dir) >> 2);
-
-        fibh.soffset = fibh.eoffset =
-                        (f_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
+        f_pos = udf_ext0_offset(dir);
+        fibh.soffset = fibh.eoffset = f_pos & (dir->i_sb->s_blocksize - 1);
 
         if (dinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
                 fibh.sbh = fibh.ebh = NULL;
-        else if (inode_bmap(dir, f_pos >> (dir->i_sb->s_blocksize_bits - 2),
+        else if (inode_bmap(dir, f_pos >> dir->i_sb->s_blocksize_bits,
                               &epos, &eloc, &elen, &offset) ==
                                         (EXT_RECORDED_ALLOCATED >> 30)) {
                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
@@ -812,7 +807,7 @@ static int empty_dir(struct inode *dir)
                 return 0;
         }
 
-        while ((f_pos < size)) {
+        while (f_pos < size) {
                 fi = udf_fileident_read(dir, &f_pos, &fibh, &cfi, &epos, &eloc,
                                         &elen, &offset);
                 if (!fi) {