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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>
This commit is contained in:
Al Viro 2013-05-15 21:02:48 -04:00
parent 5f99f4e79a
commit 5ded75ec4c
2 changed files with 70 additions and 93 deletions
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157
fs/ext3/dir.c
View File

@ -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 DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
}; };
static int ext3_dx_readdir(struct file * filp, static int ext3_dx_readdir(struct file *, struct dir_context *);
void * dirent, filldir_t filldir);
static unsigned char get_dtype(struct super_block *sb, int filetype) static unsigned char get_dtype(struct super_block *sb, int filetype)
{ {
@ -91,36 +90,30 @@ int ext3_check_dir_entry (const char * function, struct inode * dir,
return error_msg == NULL ? 1 : 0; return error_msg == NULL ? 1 : 0;
} }
static int ext3_readdir(struct file * filp, static int ext3_readdir(struct file *file, struct dir_context *ctx)
void * dirent, filldir_t filldir)
{ {
int error = 0;
unsigned long offset; unsigned long offset;
int i, stored; int i;
struct ext3_dir_entry_2 *de; struct ext3_dir_entry_2 *de;
int err; int err;
struct inode *inode = file_inode(filp); struct inode *inode = file_inode(file);
struct super_block *sb = inode->i_sb; struct super_block *sb = inode->i_sb;
int ret = 0;
int dir_has_error = 0; int dir_has_error = 0;
if (is_dx_dir(inode)) { if (is_dx_dir(inode)) {
err = ext3_dx_readdir(filp, dirent, filldir); err = ext3_dx_readdir(file, ctx);
if (err != ERR_BAD_DX_DIR) { if (err != ERR_BAD_DX_DIR)
ret = err; return err;
goto out;
}
/* /*
* We don't set the inode dirty flag since it's not * We don't set the inode dirty flag since it's not
* critical that it get flushed back to the disk. * 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 = ctx->pos & (sb->s_blocksize - 1);
offset = filp->f_pos & (sb->s_blocksize - 1);
while (!error && !stored && filp->f_pos < inode->i_size) { while (ctx->pos < inode->i_size) {
unsigned long blk = filp->f_pos >> EXT3_BLOCK_SIZE_BITS(sb); unsigned long blk = ctx->pos >> EXT3_BLOCK_SIZE_BITS(sb);
struct buffer_head map_bh; struct buffer_head map_bh;
struct buffer_head *bh = NULL; struct buffer_head *bh = NULL;
@ -129,12 +122,12 @@ static int ext3_readdir(struct file * filp,
if (err > 0) { if (err > 0) {
pgoff_t index = map_bh.b_blocknr >> pgoff_t index = map_bh.b_blocknr >>
(PAGE_CACHE_SHIFT - inode->i_blkbits); (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( page_cache_sync_readahead(
sb->s_bdev->bd_inode->i_mapping, sb->s_bdev->bd_inode->i_mapping,
&filp->f_ra, filp, &file->f_ra, file,
index, 1); 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); bh = ext3_bread(NULL, inode, blk, 0, &err);
} }
@ -146,22 +139,21 @@ static int ext3_readdir(struct file * filp,
if (!dir_has_error) { if (!dir_has_error) {
ext3_error(sb, __func__, "directory #%lu " ext3_error(sb, __func__, "directory #%lu "
"contains a hole at offset %lld", "contains a hole at offset %lld",
inode->i_ino, filp->f_pos); inode->i_ino, ctx->pos);
dir_has_error = 1; dir_has_error = 1;
} }
/* corrupt size? Maybe no more blocks to read */ /* corrupt size? Maybe no more blocks to read */
if (filp->f_pos > inode->i_blocks << 9) if (ctx->pos > inode->i_blocks << 9)
break; break;
filp->f_pos += sb->s_blocksize - offset; ctx->pos += sb->s_blocksize - offset;
continue; continue;
} }
revalidate:
/* If the dir block has changed since the last call to /* If the dir block has changed since the last call to
* readdir(2), then we might be pointing to an invalid * readdir(2), then we might be pointing to an invalid
* dirent right now. Scan from the start of the block * dirent right now. Scan from the start of the block
* to make sure. */ * 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; ) { for (i = 0; i < sb->s_blocksize && i < offset; ) {
de = (struct ext3_dir_entry_2 *) de = (struct ext3_dir_entry_2 *)
(bh->b_data + i); (bh->b_data + i);
@ -177,53 +169,40 @@ revalidate:
i += ext3_rec_len_from_disk(de->rec_len); i += ext3_rec_len_from_disk(de->rec_len);
} }
offset = i; offset = i;
filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1)) ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
| offset; | 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) { && offset < sb->s_blocksize) {
de = (struct ext3_dir_entry_2 *) (bh->b_data + offset); de = (struct ext3_dir_entry_2 *) (bh->b_data + offset);
if (!ext3_check_dir_entry ("ext3_readdir", inode, de, if (!ext3_check_dir_entry ("ext3_readdir", inode, de,
bh, offset)) { bh, offset)) {
/* On error, skip the f_pos to the /* On error, skip the to the
next block. */ next block. */
filp->f_pos = (filp->f_pos | ctx->pos = (ctx->pos |
(sb->s_blocksize - 1)) + 1; (sb->s_blocksize - 1)) + 1;
brelse (bh); break;
ret = stored;
goto out;
} }
offset += ext3_rec_len_from_disk(de->rec_len); offset += ext3_rec_len_from_disk(de->rec_len);
if (le32_to_cpu(de->inode)) { if (le32_to_cpu(de->inode)) {
/* We might block in the next section if (!dir_emit(ctx, de->name, de->name_len,
* if the data destination is le32_to_cpu(de->inode),
* currently swapped out. So, use a get_dtype(sb, de->file_type))) {
* version stamp to detect whether or brelse(bh);
* not the directory has been modified return 0;
* 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 ++;
} }
filp->f_pos += ext3_rec_len_from_disk(de->rec_len); ctx->pos += ext3_rec_len_from_disk(de->rec_len);
} }
offset = 0; offset = 0;
brelse (bh); brelse (bh);
if (ctx->pos < inode->i_size)
if (!dir_relax(inode))
return 0;
} }
out: return 0;
return ret;
} }
static inline int is_32bit_api(void) static inline int is_32bit_api(void)
@ -452,62 +431,54 @@ int ext3_htree_store_dirent(struct file *dir_file, __u32 hash,
* for all entres on the fname linked list. (Normally there is only * 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.) * one entry on the linked list, unless there are 62 bit hash collisions.)
*/ */
static int call_filldir(struct file * filp, void * dirent, static bool call_filldir(struct file *file, struct dir_context *ctx,
filldir_t filldir, struct fname *fname) struct fname *fname)
{ {
struct dir_private_info *info = filp->private_data; struct dir_private_info *info = file->private_data;
loff_t curr_pos; struct inode *inode = file_inode(file);
struct inode *inode = file_inode(filp); struct super_block *sb = inode->i_sb;
struct super_block * sb;
int error;
sb = inode->i_sb;
if (!fname) { if (!fname) {
printk("call_filldir: called with null fname?!?\n"); 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) { while (fname) {
error = filldir(dirent, fname->name, if (!dir_emit(ctx, fname->name, fname->name_len,
fname->name_len, curr_pos,
fname->inode, fname->inode,
get_dtype(sb, fname->file_type)); get_dtype(sb, fname->file_type))) {
if (error) {
filp->f_pos = curr_pos;
info->extra_fname = fname; info->extra_fname = fname;
return error; return false;
} }
fname = fname->next; fname = fname->next;
} }
return 0; return true;
} }
static int ext3_dx_readdir(struct file * filp, static int ext3_dx_readdir(struct file *file, struct dir_context *ctx)
void * dirent, filldir_t filldir)
{ {
struct dir_private_info *info = filp->private_data; struct dir_private_info *info = file->private_data;
struct inode *inode = file_inode(filp); struct inode *inode = file_inode(file);
struct fname *fname; struct fname *fname;
int ret; int ret;
if (!info) { if (!info) {
info = ext3_htree_create_dir_info(filp, filp->f_pos); info = ext3_htree_create_dir_info(file, ctx->pos);
if (!info) if (!info)
return -ENOMEM; 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 */ return 0; /* EOF */
/* Some one has messed with f_pos; reset the world */ /* 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); free_rb_tree_fname(&info->root);
info->curr_node = NULL; info->curr_node = NULL;
info->extra_fname = NULL; info->extra_fname = NULL;
info->curr_hash = pos2maj_hash(filp, filp->f_pos); info->curr_hash = pos2maj_hash(file, ctx->pos);
info->curr_minor_hash = pos2min_hash(filp, filp->f_pos); info->curr_minor_hash = pos2min_hash(file, ctx->pos);
} }
/* /*
@ -515,7 +486,7 @@ static int ext3_dx_readdir(struct file * filp,
* chain, return them first. * chain, return them first.
*/ */
if (info->extra_fname) { if (info->extra_fname) {
if (call_filldir(filp, dirent, filldir, info->extra_fname)) if (!call_filldir(file, ctx, info->extra_fname))
goto finished; goto finished;
info->extra_fname = NULL; info->extra_fname = NULL;
goto next_node; goto next_node;
@ -529,17 +500,17 @@ static int ext3_dx_readdir(struct file * filp,
* cached entries. * cached entries.
*/ */
if ((!info->curr_node) || if ((!info->curr_node) ||
(filp->f_version != inode->i_version)) { (file->f_version != inode->i_version)) {
info->curr_node = NULL; info->curr_node = NULL;
free_rb_tree_fname(&info->root); free_rb_tree_fname(&info->root);
filp->f_version = inode->i_version; file->f_version = inode->i_version;
ret = ext3_htree_fill_tree(filp, info->curr_hash, ret = ext3_htree_fill_tree(file, info->curr_hash,
info->curr_minor_hash, info->curr_minor_hash,
&info->next_hash); &info->next_hash);
if (ret < 0) if (ret < 0)
return ret; return ret;
if (ret == 0) { if (ret == 0) {
filp->f_pos = ext3_get_htree_eof(filp); ctx->pos = ext3_get_htree_eof(file);
break; break;
} }
info->curr_node = rb_first(&info->root); info->curr_node = rb_first(&info->root);
@ -548,7 +519,7 @@ static int ext3_dx_readdir(struct file * filp,
fname = rb_entry(info->curr_node, struct fname, rb_hash); fname = rb_entry(info->curr_node, struct fname, rb_hash);
info->curr_hash = fname->hash; info->curr_hash = fname->hash;
info->curr_minor_hash = fname->minor_hash; info->curr_minor_hash = fname->minor_hash;
if (call_filldir(filp, dirent, filldir, fname)) if (!call_filldir(file, ctx, fname))
break; break;
next_node: next_node:
info->curr_node = rb_next(info->curr_node); info->curr_node = rb_next(info->curr_node);
@ -559,7 +530,7 @@ static int ext3_dx_readdir(struct file * filp,
info->curr_minor_hash = fname->minor_hash; info->curr_minor_hash = fname->minor_hash;
} else { } else {
if (info->next_hash == ~0) { if (info->next_hash == ~0) {
filp->f_pos = ext3_get_htree_eof(filp); ctx->pos = ext3_get_htree_eof(file);
break; break;
} }
info->curr_hash = info->next_hash; info->curr_hash = info->next_hash;
@ -567,7 +538,7 @@ static int ext3_dx_readdir(struct file * filp,
} }
} }
finished: finished:
info->last_pos = filp->f_pos; info->last_pos = ctx->pos;
return 0; return 0;
} }
@ -582,7 +553,7 @@ static int ext3_release_dir (struct inode * inode, struct file * filp)
const struct file_operations ext3_dir_operations = { const struct file_operations ext3_dir_operations = {
.llseek = ext3_dir_llseek, .llseek = ext3_dir_llseek,
.read = generic_read_dir, .read = generic_read_dir,
.readdir = ext3_readdir, .iterate = ext3_readdir,
.unlocked_ioctl = ext3_ioctl, .unlocked_ioctl = ext3_ioctl,
#ifdef CONFIG_COMPAT #ifdef CONFIG_COMPAT
.compat_ioctl = ext3_compat_ioctl, .compat_ioctl = ext3_compat_ioctl,

6
include/linux/fs.h
View File

@ -2725,5 +2725,11 @@ static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
} }
return true; 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 */ #endif /* _LINUX_FS_H */