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[readdir] convert ext3
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new helper: dir_relax(inode).  Call when you are in location that will
_not_ be invalidated by directory modifications (block boundary, in case
of ext*).  Returns whether the directory has survived (dropping i_mutex
allows rmdir to kill the sucker; if it returns false to us, ->iterate()
is obviously done)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro committed Jun 29, 2013
1 parent 5f99f4e commit 5ded75e
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Showing 2 changed files with 70 additions and 93 deletions.
157 changes: 64 additions & 93 deletions fs/ext3/dir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,7 @@ static unsigned char ext3_filetype_table[] = {
DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
};

static int ext3_dx_readdir(struct file * filp,
void * dirent, filldir_t filldir);
static int ext3_dx_readdir(struct file *, struct dir_context *);

static unsigned char get_dtype(struct super_block *sb, int filetype)
{
Expand Down Expand Up @@ -91,36 +90,30 @@ int ext3_check_dir_entry (const char * function, struct inode * dir,
return error_msg == NULL ? 1 : 0;
}

static int ext3_readdir(struct file * filp,
void * dirent, filldir_t filldir)
static int ext3_readdir(struct file *file, struct dir_context *ctx)
{
int error = 0;
unsigned long offset;
int i, stored;
int i;
struct ext3_dir_entry_2 *de;
int err;
struct inode *inode = file_inode(filp);
struct inode *inode = file_inode(file);
struct super_block *sb = inode->i_sb;
int ret = 0;
int dir_has_error = 0;

if (is_dx_dir(inode)) {
err = ext3_dx_readdir(filp, dirent, filldir);
if (err != ERR_BAD_DX_DIR) {
ret = err;
goto out;
}
err = ext3_dx_readdir(file, ctx);
if (err != ERR_BAD_DX_DIR)
return err;
/*
* We don't set the inode dirty flag since it's not
* critical that it get flushed back to the disk.
*/
EXT3_I(file_inode(filp))->i_flags &= ~EXT3_INDEX_FL;
EXT3_I(inode)->i_flags &= ~EXT3_INDEX_FL;
}
stored = 0;
offset = filp->f_pos & (sb->s_blocksize - 1);
offset = ctx->pos & (sb->s_blocksize - 1);

while (!error && !stored && filp->f_pos < inode->i_size) {
unsigned long blk = filp->f_pos >> EXT3_BLOCK_SIZE_BITS(sb);
while (ctx->pos < inode->i_size) {
unsigned long blk = ctx->pos >> EXT3_BLOCK_SIZE_BITS(sb);
struct buffer_head map_bh;
struct buffer_head *bh = NULL;

Expand All @@ -129,12 +122,12 @@ static int ext3_readdir(struct file * filp,
if (err > 0) {
pgoff_t index = map_bh.b_blocknr >>
(PAGE_CACHE_SHIFT - inode->i_blkbits);
if (!ra_has_index(&filp->f_ra, index))
if (!ra_has_index(&file->f_ra, index))
page_cache_sync_readahead(
sb->s_bdev->bd_inode->i_mapping,
&filp->f_ra, filp,
&file->f_ra, file,
index, 1);
filp->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
file->f_ra.prev_pos = (loff_t)index << PAGE_CACHE_SHIFT;
bh = ext3_bread(NULL, inode, blk, 0, &err);
}

Expand All @@ -146,22 +139,21 @@ static int ext3_readdir(struct file * filp,
if (!dir_has_error) {
ext3_error(sb, __func__, "directory #%lu "
"contains a hole at offset %lld",
inode->i_ino, filp->f_pos);
inode->i_ino, ctx->pos);
dir_has_error = 1;
}
/* corrupt size? Maybe no more blocks to read */
if (filp->f_pos > inode->i_blocks << 9)
if (ctx->pos > inode->i_blocks << 9)
break;
filp->f_pos += sb->s_blocksize - offset;
ctx->pos += sb->s_blocksize - offset;
continue;
}

revalidate:
/* If the dir block has changed since the last call to
* readdir(2), then we might be pointing to an invalid
* dirent right now. Scan from the start of the block
* to make sure. */
if (filp->f_version != inode->i_version) {
if (offset && file->f_version != inode->i_version) {
for (i = 0; i < sb->s_blocksize && i < offset; ) {
de = (struct ext3_dir_entry_2 *)
(bh->b_data + i);
Expand All @@ -177,53 +169,40 @@ static int ext3_readdir(struct file * filp,
i += ext3_rec_len_from_disk(de->rec_len);
}
offset = i;
filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
| offset;
filp->f_version = inode->i_version;
file->f_version = inode->i_version;
}

while (!error && filp->f_pos < inode->i_size
while (ctx->pos < inode->i_size
&& offset < sb->s_blocksize) {
de = (struct ext3_dir_entry_2 *) (bh->b_data + offset);
if (!ext3_check_dir_entry ("ext3_readdir", inode, de,
bh, offset)) {
/* On error, skip the f_pos to the
/* On error, skip the to the
next block. */
filp->f_pos = (filp->f_pos |
ctx->pos = (ctx->pos |
(sb->s_blocksize - 1)) + 1;
brelse (bh);
ret = stored;
goto out;
break;
}
offset += ext3_rec_len_from_disk(de->rec_len);
if (le32_to_cpu(de->inode)) {
/* We might block in the next section
* if the data destination is
* currently swapped out. So, use a
* version stamp to detect whether or
* not the directory has been modified
* during the copy operation.
*/
u64 version = filp->f_version;

error = filldir(dirent, de->name,
de->name_len,
filp->f_pos,
le32_to_cpu(de->inode),
get_dtype(sb, de->file_type));
if (error)
break;
if (version != filp->f_version)
goto revalidate;
stored ++;
if (!dir_emit(ctx, de->name, de->name_len,
le32_to_cpu(de->inode),
get_dtype(sb, de->file_type))) {
brelse(bh);
return 0;
}
}
filp->f_pos += ext3_rec_len_from_disk(de->rec_len);
ctx->pos += ext3_rec_len_from_disk(de->rec_len);
}
offset = 0;
brelse (bh);
if (ctx->pos < inode->i_size)
if (!dir_relax(inode))
return 0;
}
out:
return ret;
return 0;
}

static inline int is_32bit_api(void)
Expand Down Expand Up @@ -452,70 +431,62 @@ int ext3_htree_store_dirent(struct file *dir_file, __u32 hash,
* for all entres on the fname linked list. (Normally there is only
* one entry on the linked list, unless there are 62 bit hash collisions.)
*/
static int call_filldir(struct file * filp, void * dirent,
filldir_t filldir, struct fname *fname)
static bool call_filldir(struct file *file, struct dir_context *ctx,
struct fname *fname)
{
struct dir_private_info *info = filp->private_data;
loff_t curr_pos;
struct inode *inode = file_inode(filp);
struct super_block * sb;
int error;

sb = inode->i_sb;
struct dir_private_info *info = file->private_data;
struct inode *inode = file_inode(file);
struct super_block *sb = inode->i_sb;

if (!fname) {
printk("call_filldir: called with null fname?!?\n");
return 0;
return true;
}
curr_pos = hash2pos(filp, fname->hash, fname->minor_hash);
ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
while (fname) {
error = filldir(dirent, fname->name,
fname->name_len, curr_pos,
if (!dir_emit(ctx, fname->name, fname->name_len,
fname->inode,
get_dtype(sb, fname->file_type));
if (error) {
filp->f_pos = curr_pos;
get_dtype(sb, fname->file_type))) {
info->extra_fname = fname;
return error;
return false;
}
fname = fname->next;
}
return 0;
return true;
}

static int ext3_dx_readdir(struct file * filp,
void * dirent, filldir_t filldir)
static int ext3_dx_readdir(struct file *file, struct dir_context *ctx)
{
struct dir_private_info *info = filp->private_data;
struct inode *inode = file_inode(filp);
struct dir_private_info *info = file->private_data;
struct inode *inode = file_inode(file);
struct fname *fname;
int ret;

if (!info) {
info = ext3_htree_create_dir_info(filp, filp->f_pos);
info = ext3_htree_create_dir_info(file, ctx->pos);
if (!info)
return -ENOMEM;
filp->private_data = info;
file->private_data = info;
}

if (filp->f_pos == ext3_get_htree_eof(filp))
if (ctx->pos == ext3_get_htree_eof(file))
return 0; /* EOF */

/* Some one has messed with f_pos; reset the world */
if (info->last_pos != filp->f_pos) {
if (info->last_pos != ctx->pos) {
free_rb_tree_fname(&info->root);
info->curr_node = NULL;
info->extra_fname = NULL;
info->curr_hash = pos2maj_hash(filp, filp->f_pos);
info->curr_minor_hash = pos2min_hash(filp, filp->f_pos);
info->curr_hash = pos2maj_hash(file, ctx->pos);
info->curr_minor_hash = pos2min_hash(file, ctx->pos);
}

/*
* If there are any leftover names on the hash collision
* chain, return them first.
*/
if (info->extra_fname) {
if (call_filldir(filp, dirent, filldir, info->extra_fname))
if (!call_filldir(file, ctx, info->extra_fname))
goto finished;
info->extra_fname = NULL;
goto next_node;
Expand All @@ -529,17 +500,17 @@ static int ext3_dx_readdir(struct file * filp,
* cached entries.
*/
if ((!info->curr_node) ||
(filp->f_version != inode->i_version)) {
(file->f_version != inode->i_version)) {
info->curr_node = NULL;
free_rb_tree_fname(&info->root);
filp->f_version = inode->i_version;
ret = ext3_htree_fill_tree(filp, info->curr_hash,
file->f_version = inode->i_version;
ret = ext3_htree_fill_tree(file, info->curr_hash,
info->curr_minor_hash,
&info->next_hash);
if (ret < 0)
return ret;
if (ret == 0) {
filp->f_pos = ext3_get_htree_eof(filp);
ctx->pos = ext3_get_htree_eof(file);
break;
}
info->curr_node = rb_first(&info->root);
Expand All @@ -548,7 +519,7 @@ static int ext3_dx_readdir(struct file * filp,
fname = rb_entry(info->curr_node, struct fname, rb_hash);
info->curr_hash = fname->hash;
info->curr_minor_hash = fname->minor_hash;
if (call_filldir(filp, dirent, filldir, fname))
if (!call_filldir(file, ctx, fname))
break;
next_node:
info->curr_node = rb_next(info->curr_node);
Expand All @@ -559,15 +530,15 @@ static int ext3_dx_readdir(struct file * filp,
info->curr_minor_hash = fname->minor_hash;
} else {
if (info->next_hash == ~0) {
filp->f_pos = ext3_get_htree_eof(filp);
ctx->pos = ext3_get_htree_eof(file);
break;
}
info->curr_hash = info->next_hash;
info->curr_minor_hash = 0;
}
}
finished:
info->last_pos = filp->f_pos;
info->last_pos = ctx->pos;
return 0;
}

Expand All @@ -582,7 +553,7 @@ static int ext3_release_dir (struct inode * inode, struct file * filp)
const struct file_operations ext3_dir_operations = {
.llseek = ext3_dir_llseek,
.read = generic_read_dir,
.readdir = ext3_readdir,
.iterate = ext3_readdir,
.unlocked_ioctl = ext3_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = ext3_compat_ioctl,
Expand Down
6 changes: 6 additions & 0 deletions include/linux/fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2725,5 +2725,11 @@ static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
}
return true;
}
static inline bool dir_relax(struct inode *inode)
{
mutex_unlock(&inode->i_mutex);
mutex_lock(&inode->i_mutex);
return !IS_DEADDIR(inode);
}

#endif /* _LINUX_FS_H */

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