* ext3: return 32/64-bit dir name hash according to usage type
@ 2012-04-26 18:10 Eric Sandeen
2012-04-26 18:26 ` J. Bruce Fields
2012-04-26 18:57 ` Jan Kara
0 siblings, 2 replies; 4+ messages in thread
From: Eric Sandeen @ 2012-04-26 18:10 UTC (permalink / raw)
To: ext4 development; +Cc: Jan Kara, Bruce Fields, Bernd Schubert
This is based on commit d1f5273e9adb40724a85272f248f210dc4ce919a
ext4: return 32/64-bit dir name hash according to usage type
by Fan Yong <yong.fan@whamcloud.com>
Traditionally ext2/3/4 has returned a 32-bit hash value from llseek()
to appease NFSv2, which can only handle a 32-bit cookie for seekdir()
and telldir(). However, this causes problems if there are 32-bit hash
collisions, since the NFSv2 server can get stuck resending the same
entries from the directory repeatedly.
Allow ext3 to return a full 64-bit hash (both major and minor) for
telldir to decrease the chance of hash collisions.
This patch does implement a new ext3_dir_llseek op, because with 64-bit
hashes, nfs will attempt to seek to a hash "offset" which is much
larger than ext3's s_maxbytes. So for dx dirs, we call
generic_file_llseek_size() with the appropriate max hash value as the
maximum seekable size. Otherwise we just pass through to
generic_file_llseek().
Patch-updated-by: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Patch-updated-by: Eric Sandeen <sandeen@redhat.com>
(blame us if something is not correct)
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---
diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
index cc761ad..92490e9 100644
--- a/fs/ext3/dir.c
+++ b/fs/ext3/dir.c
@@ -21,30 +21,15 @@
*
*/
+#include <linux/compat.h>
#include "ext3.h"
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_readdir(struct file *, void *, filldir_t);
static int ext3_dx_readdir(struct file * filp,
void * dirent, filldir_t filldir);
-static int ext3_release_dir (struct inode * inode,
- struct file * filp);
-
-const struct file_operations ext3_dir_operations = {
- .llseek = generic_file_llseek,
- .read = generic_read_dir,
- .readdir = ext3_readdir, /* we take BKL. needed?*/
- .unlocked_ioctl = ext3_ioctl,
-#ifdef CONFIG_COMPAT
- .compat_ioctl = ext3_compat_ioctl,
-#endif
- .fsync = ext3_sync_file, /* BKL held */
- .release = ext3_release_dir,
-};
-
static unsigned char get_dtype(struct super_block *sb, int filetype)
{
@@ -55,6 +40,25 @@ static unsigned char get_dtype(struct super_block *sb, int filetype)
return (ext3_filetype_table[filetype]);
}
+/**
+ * Check if the given dir-inode refers to an htree-indexed directory
+ * (or a directory which chould potentially get coverted to use htree
+ * indexing).
+ *
+ * Return 1 if it is a dx dir, 0 if not
+ */
+static int is_dx_dir(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+
+ if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
+ EXT3_FEATURE_COMPAT_DIR_INDEX) &&
+ ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
+ ((inode->i_size >> sb->s_blocksize_bits) == 1)))
+ return 1;
+
+ return 0;
+}
int ext3_check_dir_entry (const char * function, struct inode * dir,
struct ext3_dir_entry_2 * de,
@@ -94,18 +98,13 @@ static int ext3_readdir(struct file * filp,
unsigned long offset;
int i, stored;
struct ext3_dir_entry_2 *de;
- struct super_block *sb;
int err;
struct inode *inode = filp->f_path.dentry->d_inode;
+ struct super_block *sb = inode->i_sb;
int ret = 0;
int dir_has_error = 0;
- sb = inode->i_sb;
-
- if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
- EXT3_FEATURE_COMPAT_DIR_INDEX) &&
- ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
- ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
+ if (is_dx_dir(inode)) {
err = ext3_dx_readdir(filp, dirent, filldir);
if (err != ERR_BAD_DX_DIR) {
ret = err;
@@ -227,22 +226,87 @@ out:
return ret;
}
+static inline int is_32bit_api(void)
+{
+#ifdef CONFIG_COMPAT
+ return is_compat_task();
+#else
+ return (BITS_PER_LONG == 32);
+#endif
+}
+
/*
* These functions convert from the major/minor hash to an f_pos
- * value.
+ * value for dx directories
*
- * Currently we only use major hash numer. This is unfortunate, but
- * on 32-bit machines, the same VFS interface is used for lseek and
- * llseek, so if we use the 64 bit offset, then the 32-bit versions of
- * lseek/telldir/seekdir will blow out spectacularly, and from within
- * the ext2 low-level routine, we don't know if we're being called by
- * a 64-bit version of the system call or the 32-bit version of the
- * system call. Worse yet, NFSv2 only allows for a 32-bit readdir
- * cookie. Sigh.
+ * Upper layer (for example NFS) should specify FMODE_32BITHASH or
+ * FMODE_64BITHASH explicitly. On the other hand, we allow ext3 to be mounted
+ * directly on both 32-bit and 64-bit nodes, under such case, neither
+ * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
*/
-#define hash2pos(major, minor) (major >> 1)
-#define pos2maj_hash(pos) ((pos << 1) & 0xffffffff)
-#define pos2min_hash(pos) (0)
+static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
+{
+ if ((filp->f_mode & FMODE_32BITHASH) ||
+ (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+ return major >> 1;
+ else
+ return ((__u64)(major >> 1) << 32) | (__u64)minor;
+}
+
+static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
+{
+ if ((filp->f_mode & FMODE_32BITHASH) ||
+ (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+ return (pos << 1) & 0xffffffff;
+ else
+ return ((pos >> 32) << 1) & 0xffffffff;
+}
+
+static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
+{
+ if ((filp->f_mode & FMODE_32BITHASH) ||
+ (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+ return 0;
+ else
+ return pos & 0xffffffff;
+}
+
+/*
+ * Return 32- or 64-bit end-of-file for dx directories
+ */
+static inline loff_t ext3_get_htree_eof(struct file *filp)
+{
+ if ((filp->f_mode & FMODE_32BITHASH) ||
+ (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+ return EXT3_HTREE_EOF_32BIT;
+ else
+ return EXT3_HTREE_EOF_64BIT;
+}
+
+
+/*
+ * ext3_dir_llseek() calls generic_file_llseek[_size]() to handle both
+ * non-htree and htree directories, where the "offset" is in terms
+ * of the filename hash value instead of the byte offset.
+ *
+ * Because we may return a 64-bit hash that is well beyond s_maxbytes,
+ * we need to pass the max hash as the maximum allowable offset in
+ * the htree directory case.
+ *
+ * NOTE: offsets obtained *before* ext3_set_inode_flag(dir, EXT3_INODE_INDEX)
+ * will be invalid once the directory was converted into a dx directory
+ */
+loff_t ext3_dir_llseek(struct file *file, loff_t offset, int origin)
+{
+ struct inode *inode = file->f_mapping->host;
+ int dx_dir = is_dx_dir(inode);
+
+ if (likely(dx_dir))
+ return generic_file_llseek_size(file, offset, origin,
+ ext3_get_htree_eof(file));
+ else
+ return generic_file_llseek(file, offset, origin);
+}
/*
* This structure holds the nodes of the red-black tree used to store
@@ -303,15 +367,16 @@ static void free_rb_tree_fname(struct rb_root *root)
}
-static struct dir_private_info *ext3_htree_create_dir_info(loff_t pos)
+static struct dir_private_info *ext3_htree_create_dir_info(struct file *filp,
+ loff_t pos)
{
struct dir_private_info *p;
p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
if (!p)
return NULL;
- p->curr_hash = pos2maj_hash(pos);
- p->curr_minor_hash = pos2min_hash(pos);
+ p->curr_hash = pos2maj_hash(filp, pos);
+ p->curr_minor_hash = pos2min_hash(filp, pos);
return p;
}
@@ -401,7 +466,7 @@ static int call_filldir(struct file * filp, void * dirent,
printk("call_filldir: called with null fname?!?\n");
return 0;
}
- curr_pos = hash2pos(fname->hash, fname->minor_hash);
+ curr_pos = hash2pos(filp, fname->hash, fname->minor_hash);
while (fname) {
error = filldir(dirent, fname->name,
fname->name_len, curr_pos,
@@ -426,13 +491,13 @@ static int ext3_dx_readdir(struct file * filp,
int ret;
if (!info) {
- info = ext3_htree_create_dir_info(filp->f_pos);
+ info = ext3_htree_create_dir_info(filp, filp->f_pos);
if (!info)
return -ENOMEM;
filp->private_data = info;
}
- if (filp->f_pos == EXT3_HTREE_EOF)
+ if (filp->f_pos == ext3_get_htree_eof(filp))
return 0; /* EOF */
/* Some one has messed with f_pos; reset the world */
@@ -440,8 +505,8 @@ static int ext3_dx_readdir(struct file * filp,
free_rb_tree_fname(&info->root);
info->curr_node = NULL;
info->extra_fname = NULL;
- info->curr_hash = pos2maj_hash(filp->f_pos);
- info->curr_minor_hash = pos2min_hash(filp->f_pos);
+ info->curr_hash = pos2maj_hash(filp, filp->f_pos);
+ info->curr_minor_hash = pos2min_hash(filp, filp->f_pos);
}
/*
@@ -473,7 +538,7 @@ static int ext3_dx_readdir(struct file * filp,
if (ret < 0)
return ret;
if (ret == 0) {
- filp->f_pos = EXT3_HTREE_EOF;
+ filp->f_pos = ext3_get_htree_eof(filp);
break;
}
info->curr_node = rb_first(&info->root);
@@ -493,7 +558,7 @@ 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_HTREE_EOF;
+ filp->f_pos = ext3_get_htree_eof(filp);
break;
}
info->curr_hash = info->next_hash;
@@ -512,3 +577,15 @@ static int ext3_release_dir (struct inode * inode, struct file * filp)
return 0;
}
+
+const struct file_operations ext3_dir_operations = {
+ .llseek = ext3_dir_llseek,
+ .read = generic_read_dir,
+ .readdir = ext3_readdir,
+ .unlocked_ioctl = ext3_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = ext3_compat_ioctl,
+#endif
+ .fsync = ext3_sync_file,
+ .release = ext3_release_dir,
+};
diff --git a/fs/ext3/ext3.h b/fs/ext3/ext3.h
index b6515fd..fe5bef7 100644
--- a/fs/ext3/ext3.h
+++ b/fs/ext3/ext3.h
@@ -920,7 +920,11 @@ struct dx_hash_info
u32 *seed;
};
-#define EXT3_HTREE_EOF 0x7fffffff
+
+/* 32 and 64 bit signed EOF for dx directories */
+#define EXT3_HTREE_EOF_32BIT ((1UL << (32 - 1)) - 1)
+#define EXT3_HTREE_EOF_64BIT ((1ULL << (64 - 1)) - 1)
+
/*
* Control parameters used by ext3_htree_next_block
diff --git a/fs/ext3/hash.c b/fs/ext3/hash.c
index d10231d..ede315c 100644
--- a/fs/ext3/hash.c
+++ b/fs/ext3/hash.c
@@ -198,8 +198,8 @@ int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
return -1;
}
hash = hash & ~1;
- if (hash == (EXT3_HTREE_EOF << 1))
- hash = (EXT3_HTREE_EOF-1) << 1;
+ if (hash == (EXT3_HTREE_EOF_32BIT << 1))
+ hash = (EXT3_HTREE_EOF_32BIT - 1) << 1;
hinfo->hash = hash;
hinfo->minor_hash = minor_hash;
return 0;
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: ext3: return 32/64-bit dir name hash according to usage type
2012-04-26 18:10 ext3: return 32/64-bit dir name hash according to usage type Eric Sandeen
@ 2012-04-26 18:26 ` J. Bruce Fields
2012-04-26 18:28 ` Eric Sandeen
2012-04-26 18:57 ` Jan Kara
1 sibling, 1 reply; 4+ messages in thread
From: J. Bruce Fields @ 2012-04-26 18:26 UTC (permalink / raw)
To: Eric Sandeen; +Cc: ext4 development, Jan Kara, Bernd Schubert
How are you testing this?
--b.
On Thu, Apr 26, 2012 at 01:10:39PM -0500, Eric Sandeen wrote:
> This is based on commit d1f5273e9adb40724a85272f248f210dc4ce919a
> ext4: return 32/64-bit dir name hash according to usage type
> by Fan Yong <yong.fan@whamcloud.com>
>
> Traditionally ext2/3/4 has returned a 32-bit hash value from llseek()
> to appease NFSv2, which can only handle a 32-bit cookie for seekdir()
> and telldir(). However, this causes problems if there are 32-bit hash
> collisions, since the NFSv2 server can get stuck resending the same
> entries from the directory repeatedly.
>
> Allow ext3 to return a full 64-bit hash (both major and minor) for
> telldir to decrease the chance of hash collisions.
>
> This patch does implement a new ext3_dir_llseek op, because with 64-bit
> hashes, nfs will attempt to seek to a hash "offset" which is much
> larger than ext3's s_maxbytes. So for dx dirs, we call
> generic_file_llseek_size() with the appropriate max hash value as the
> maximum seekable size. Otherwise we just pass through to
> generic_file_llseek().
>
> Patch-updated-by: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
> Patch-updated-by: Eric Sandeen <sandeen@redhat.com>
> (blame us if something is not correct)
>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
>
> diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
> index cc761ad..92490e9 100644
> --- a/fs/ext3/dir.c
> +++ b/fs/ext3/dir.c
> @@ -21,30 +21,15 @@
> *
> */
>
> +#include <linux/compat.h>
> #include "ext3.h"
>
> 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_readdir(struct file *, void *, filldir_t);
> static int ext3_dx_readdir(struct file * filp,
> void * dirent, filldir_t filldir);
> -static int ext3_release_dir (struct inode * inode,
> - struct file * filp);
> -
> -const struct file_operations ext3_dir_operations = {
> - .llseek = generic_file_llseek,
> - .read = generic_read_dir,
> - .readdir = ext3_readdir, /* we take BKL. needed?*/
> - .unlocked_ioctl = ext3_ioctl,
> -#ifdef CONFIG_COMPAT
> - .compat_ioctl = ext3_compat_ioctl,
> -#endif
> - .fsync = ext3_sync_file, /* BKL held */
> - .release = ext3_release_dir,
> -};
> -
>
> static unsigned char get_dtype(struct super_block *sb, int filetype)
> {
> @@ -55,6 +40,25 @@ static unsigned char get_dtype(struct super_block *sb, int filetype)
> return (ext3_filetype_table[filetype]);
> }
>
> +/**
> + * Check if the given dir-inode refers to an htree-indexed directory
> + * (or a directory which chould potentially get coverted to use htree
> + * indexing).
> + *
> + * Return 1 if it is a dx dir, 0 if not
> + */
> +static int is_dx_dir(struct inode *inode)
> +{
> + struct super_block *sb = inode->i_sb;
> +
> + if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
> + EXT3_FEATURE_COMPAT_DIR_INDEX) &&
> + ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
> + ((inode->i_size >> sb->s_blocksize_bits) == 1)))
> + return 1;
> +
> + return 0;
> +}
>
> int ext3_check_dir_entry (const char * function, struct inode * dir,
> struct ext3_dir_entry_2 * de,
> @@ -94,18 +98,13 @@ static int ext3_readdir(struct file * filp,
> unsigned long offset;
> int i, stored;
> struct ext3_dir_entry_2 *de;
> - struct super_block *sb;
> int err;
> struct inode *inode = filp->f_path.dentry->d_inode;
> + struct super_block *sb = inode->i_sb;
> int ret = 0;
> int dir_has_error = 0;
>
> - sb = inode->i_sb;
> -
> - if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
> - EXT3_FEATURE_COMPAT_DIR_INDEX) &&
> - ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
> - ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
> + if (is_dx_dir(inode)) {
> err = ext3_dx_readdir(filp, dirent, filldir);
> if (err != ERR_BAD_DX_DIR) {
> ret = err;
> @@ -227,22 +226,87 @@ out:
> return ret;
> }
>
> +static inline int is_32bit_api(void)
> +{
> +#ifdef CONFIG_COMPAT
> + return is_compat_task();
> +#else
> + return (BITS_PER_LONG == 32);
> +#endif
> +}
> +
> /*
> * These functions convert from the major/minor hash to an f_pos
> - * value.
> + * value for dx directories
> *
> - * Currently we only use major hash numer. This is unfortunate, but
> - * on 32-bit machines, the same VFS interface is used for lseek and
> - * llseek, so if we use the 64 bit offset, then the 32-bit versions of
> - * lseek/telldir/seekdir will blow out spectacularly, and from within
> - * the ext2 low-level routine, we don't know if we're being called by
> - * a 64-bit version of the system call or the 32-bit version of the
> - * system call. Worse yet, NFSv2 only allows for a 32-bit readdir
> - * cookie. Sigh.
> + * Upper layer (for example NFS) should specify FMODE_32BITHASH or
> + * FMODE_64BITHASH explicitly. On the other hand, we allow ext3 to be mounted
> + * directly on both 32-bit and 64-bit nodes, under such case, neither
> + * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
> */
> -#define hash2pos(major, minor) (major >> 1)
> -#define pos2maj_hash(pos) ((pos << 1) & 0xffffffff)
> -#define pos2min_hash(pos) (0)
> +static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
> +{
> + if ((filp->f_mode & FMODE_32BITHASH) ||
> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
> + return major >> 1;
> + else
> + return ((__u64)(major >> 1) << 32) | (__u64)minor;
> +}
> +
> +static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
> +{
> + if ((filp->f_mode & FMODE_32BITHASH) ||
> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
> + return (pos << 1) & 0xffffffff;
> + else
> + return ((pos >> 32) << 1) & 0xffffffff;
> +}
> +
> +static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
> +{
> + if ((filp->f_mode & FMODE_32BITHASH) ||
> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
> + return 0;
> + else
> + return pos & 0xffffffff;
> +}
> +
> +/*
> + * Return 32- or 64-bit end-of-file for dx directories
> + */
> +static inline loff_t ext3_get_htree_eof(struct file *filp)
> +{
> + if ((filp->f_mode & FMODE_32BITHASH) ||
> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
> + return EXT3_HTREE_EOF_32BIT;
> + else
> + return EXT3_HTREE_EOF_64BIT;
> +}
> +
> +
> +/*
> + * ext3_dir_llseek() calls generic_file_llseek[_size]() to handle both
> + * non-htree and htree directories, where the "offset" is in terms
> + * of the filename hash value instead of the byte offset.
> + *
> + * Because we may return a 64-bit hash that is well beyond s_maxbytes,
> + * we need to pass the max hash as the maximum allowable offset in
> + * the htree directory case.
> + *
> + * NOTE: offsets obtained *before* ext3_set_inode_flag(dir, EXT3_INODE_INDEX)
> + * will be invalid once the directory was converted into a dx directory
> + */
> +loff_t ext3_dir_llseek(struct file *file, loff_t offset, int origin)
> +{
> + struct inode *inode = file->f_mapping->host;
> + int dx_dir = is_dx_dir(inode);
> +
> + if (likely(dx_dir))
> + return generic_file_llseek_size(file, offset, origin,
> + ext3_get_htree_eof(file));
> + else
> + return generic_file_llseek(file, offset, origin);
> +}
>
> /*
> * This structure holds the nodes of the red-black tree used to store
> @@ -303,15 +367,16 @@ static void free_rb_tree_fname(struct rb_root *root)
> }
>
>
> -static struct dir_private_info *ext3_htree_create_dir_info(loff_t pos)
> +static struct dir_private_info *ext3_htree_create_dir_info(struct file *filp,
> + loff_t pos)
> {
> struct dir_private_info *p;
>
> p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
> if (!p)
> return NULL;
> - p->curr_hash = pos2maj_hash(pos);
> - p->curr_minor_hash = pos2min_hash(pos);
> + p->curr_hash = pos2maj_hash(filp, pos);
> + p->curr_minor_hash = pos2min_hash(filp, pos);
> return p;
> }
>
> @@ -401,7 +466,7 @@ static int call_filldir(struct file * filp, void * dirent,
> printk("call_filldir: called with null fname?!?\n");
> return 0;
> }
> - curr_pos = hash2pos(fname->hash, fname->minor_hash);
> + curr_pos = hash2pos(filp, fname->hash, fname->minor_hash);
> while (fname) {
> error = filldir(dirent, fname->name,
> fname->name_len, curr_pos,
> @@ -426,13 +491,13 @@ static int ext3_dx_readdir(struct file * filp,
> int ret;
>
> if (!info) {
> - info = ext3_htree_create_dir_info(filp->f_pos);
> + info = ext3_htree_create_dir_info(filp, filp->f_pos);
> if (!info)
> return -ENOMEM;
> filp->private_data = info;
> }
>
> - if (filp->f_pos == EXT3_HTREE_EOF)
> + if (filp->f_pos == ext3_get_htree_eof(filp))
> return 0; /* EOF */
>
> /* Some one has messed with f_pos; reset the world */
> @@ -440,8 +505,8 @@ static int ext3_dx_readdir(struct file * filp,
> free_rb_tree_fname(&info->root);
> info->curr_node = NULL;
> info->extra_fname = NULL;
> - info->curr_hash = pos2maj_hash(filp->f_pos);
> - info->curr_minor_hash = pos2min_hash(filp->f_pos);
> + info->curr_hash = pos2maj_hash(filp, filp->f_pos);
> + info->curr_minor_hash = pos2min_hash(filp, filp->f_pos);
> }
>
> /*
> @@ -473,7 +538,7 @@ static int ext3_dx_readdir(struct file * filp,
> if (ret < 0)
> return ret;
> if (ret == 0) {
> - filp->f_pos = EXT3_HTREE_EOF;
> + filp->f_pos = ext3_get_htree_eof(filp);
> break;
> }
> info->curr_node = rb_first(&info->root);
> @@ -493,7 +558,7 @@ 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_HTREE_EOF;
> + filp->f_pos = ext3_get_htree_eof(filp);
> break;
> }
> info->curr_hash = info->next_hash;
> @@ -512,3 +577,15 @@ static int ext3_release_dir (struct inode * inode, struct file * filp)
>
> return 0;
> }
> +
> +const struct file_operations ext3_dir_operations = {
> + .llseek = ext3_dir_llseek,
> + .read = generic_read_dir,
> + .readdir = ext3_readdir,
> + .unlocked_ioctl = ext3_ioctl,
> +#ifdef CONFIG_COMPAT
> + .compat_ioctl = ext3_compat_ioctl,
> +#endif
> + .fsync = ext3_sync_file,
> + .release = ext3_release_dir,
> +};
> diff --git a/fs/ext3/ext3.h b/fs/ext3/ext3.h
> index b6515fd..fe5bef7 100644
> --- a/fs/ext3/ext3.h
> +++ b/fs/ext3/ext3.h
> @@ -920,7 +920,11 @@ struct dx_hash_info
> u32 *seed;
> };
>
> -#define EXT3_HTREE_EOF 0x7fffffff
> +
> +/* 32 and 64 bit signed EOF for dx directories */
> +#define EXT3_HTREE_EOF_32BIT ((1UL << (32 - 1)) - 1)
> +#define EXT3_HTREE_EOF_64BIT ((1ULL << (64 - 1)) - 1)
> +
>
> /*
> * Control parameters used by ext3_htree_next_block
> diff --git a/fs/ext3/hash.c b/fs/ext3/hash.c
> index d10231d..ede315c 100644
> --- a/fs/ext3/hash.c
> +++ b/fs/ext3/hash.c
> @@ -198,8 +198,8 @@ int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
> return -1;
> }
> hash = hash & ~1;
> - if (hash == (EXT3_HTREE_EOF << 1))
> - hash = (EXT3_HTREE_EOF-1) << 1;
> + if (hash == (EXT3_HTREE_EOF_32BIT << 1))
> + hash = (EXT3_HTREE_EOF_32BIT - 1) << 1;
> hinfo->hash = hash;
> hinfo->minor_hash = minor_hash;
> return 0;
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: ext3: return 32/64-bit dir name hash according to usage type
2012-04-26 18:26 ` J. Bruce Fields
@ 2012-04-26 18:28 ` Eric Sandeen
0 siblings, 0 replies; 4+ messages in thread
From: Eric Sandeen @ 2012-04-26 18:28 UTC (permalink / raw)
To: J. Bruce Fields; +Cc: ext4 development, Jan Kara, Bernd Schubert
On 4/26/12 1:26 PM, J. Bruce Fields wrote:
> How are you testing this?
Basically as was suggested in the first ext4 patch series:
I created a filesystem with 600,000 files in a dir:
for x in $(seq 1 600000); do touch $x; done
then exported and mounted that fs to localhost:
mount -t nfs localhost:/mnt/export /mnt/nfs
and then looked for dups:
ls -l | dup -d
If you have more .... substantial nfs testing I could do I'm all ears :)
-Eric
> --b.
>
> On Thu, Apr 26, 2012 at 01:10:39PM -0500, Eric Sandeen wrote:
>> This is based on commit d1f5273e9adb40724a85272f248f210dc4ce919a
>> ext4: return 32/64-bit dir name hash according to usage type
>> by Fan Yong <yong.fan@whamcloud.com>
>>
>> Traditionally ext2/3/4 has returned a 32-bit hash value from llseek()
>> to appease NFSv2, which can only handle a 32-bit cookie for seekdir()
>> and telldir(). However, this causes problems if there are 32-bit hash
>> collisions, since the NFSv2 server can get stuck resending the same
>> entries from the directory repeatedly.
>>
>> Allow ext3 to return a full 64-bit hash (both major and minor) for
>> telldir to decrease the chance of hash collisions.
>>
>> This patch does implement a new ext3_dir_llseek op, because with 64-bit
>> hashes, nfs will attempt to seek to a hash "offset" which is much
>> larger than ext3's s_maxbytes. So for dx dirs, we call
>> generic_file_llseek_size() with the appropriate max hash value as the
>> maximum seekable size. Otherwise we just pass through to
>> generic_file_llseek().
>>
>> Patch-updated-by: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
>> Patch-updated-by: Eric Sandeen <sandeen@redhat.com>
>> (blame us if something is not correct)
>>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> ---
>>
>> diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
>> index cc761ad..92490e9 100644
>> --- a/fs/ext3/dir.c
>> +++ b/fs/ext3/dir.c
>> @@ -21,30 +21,15 @@
>> *
>> */
>>
>> +#include <linux/compat.h>
>> #include "ext3.h"
>>
>> 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_readdir(struct file *, void *, filldir_t);
>> static int ext3_dx_readdir(struct file * filp,
>> void * dirent, filldir_t filldir);
>> -static int ext3_release_dir (struct inode * inode,
>> - struct file * filp);
>> -
>> -const struct file_operations ext3_dir_operations = {
>> - .llseek = generic_file_llseek,
>> - .read = generic_read_dir,
>> - .readdir = ext3_readdir, /* we take BKL. needed?*/
>> - .unlocked_ioctl = ext3_ioctl,
>> -#ifdef CONFIG_COMPAT
>> - .compat_ioctl = ext3_compat_ioctl,
>> -#endif
>> - .fsync = ext3_sync_file, /* BKL held */
>> - .release = ext3_release_dir,
>> -};
>> -
>>
>> static unsigned char get_dtype(struct super_block *sb, int filetype)
>> {
>> @@ -55,6 +40,25 @@ static unsigned char get_dtype(struct super_block *sb, int filetype)
>> return (ext3_filetype_table[filetype]);
>> }
>>
>> +/**
>> + * Check if the given dir-inode refers to an htree-indexed directory
>> + * (or a directory which chould potentially get coverted to use htree
>> + * indexing).
>> + *
>> + * Return 1 if it is a dx dir, 0 if not
>> + */
>> +static int is_dx_dir(struct inode *inode)
>> +{
>> + struct super_block *sb = inode->i_sb;
>> +
>> + if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
>> + EXT3_FEATURE_COMPAT_DIR_INDEX) &&
>> + ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
>> + ((inode->i_size >> sb->s_blocksize_bits) == 1)))
>> + return 1;
>> +
>> + return 0;
>> +}
>>
>> int ext3_check_dir_entry (const char * function, struct inode * dir,
>> struct ext3_dir_entry_2 * de,
>> @@ -94,18 +98,13 @@ static int ext3_readdir(struct file * filp,
>> unsigned long offset;
>> int i, stored;
>> struct ext3_dir_entry_2 *de;
>> - struct super_block *sb;
>> int err;
>> struct inode *inode = filp->f_path.dentry->d_inode;
>> + struct super_block *sb = inode->i_sb;
>> int ret = 0;
>> int dir_has_error = 0;
>>
>> - sb = inode->i_sb;
>> -
>> - if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
>> - EXT3_FEATURE_COMPAT_DIR_INDEX) &&
>> - ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
>> - ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
>> + if (is_dx_dir(inode)) {
>> err = ext3_dx_readdir(filp, dirent, filldir);
>> if (err != ERR_BAD_DX_DIR) {
>> ret = err;
>> @@ -227,22 +226,87 @@ out:
>> return ret;
>> }
>>
>> +static inline int is_32bit_api(void)
>> +{
>> +#ifdef CONFIG_COMPAT
>> + return is_compat_task();
>> +#else
>> + return (BITS_PER_LONG == 32);
>> +#endif
>> +}
>> +
>> /*
>> * These functions convert from the major/minor hash to an f_pos
>> - * value.
>> + * value for dx directories
>> *
>> - * Currently we only use major hash numer. This is unfortunate, but
>> - * on 32-bit machines, the same VFS interface is used for lseek and
>> - * llseek, so if we use the 64 bit offset, then the 32-bit versions of
>> - * lseek/telldir/seekdir will blow out spectacularly, and from within
>> - * the ext2 low-level routine, we don't know if we're being called by
>> - * a 64-bit version of the system call or the 32-bit version of the
>> - * system call. Worse yet, NFSv2 only allows for a 32-bit readdir
>> - * cookie. Sigh.
>> + * Upper layer (for example NFS) should specify FMODE_32BITHASH or
>> + * FMODE_64BITHASH explicitly. On the other hand, we allow ext3 to be mounted
>> + * directly on both 32-bit and 64-bit nodes, under such case, neither
>> + * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
>> */
>> -#define hash2pos(major, minor) (major >> 1)
>> -#define pos2maj_hash(pos) ((pos << 1) & 0xffffffff)
>> -#define pos2min_hash(pos) (0)
>> +static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
>> +{
>> + if ((filp->f_mode & FMODE_32BITHASH) ||
>> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
>> + return major >> 1;
>> + else
>> + return ((__u64)(major >> 1) << 32) | (__u64)minor;
>> +}
>> +
>> +static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
>> +{
>> + if ((filp->f_mode & FMODE_32BITHASH) ||
>> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
>> + return (pos << 1) & 0xffffffff;
>> + else
>> + return ((pos >> 32) << 1) & 0xffffffff;
>> +}
>> +
>> +static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
>> +{
>> + if ((filp->f_mode & FMODE_32BITHASH) ||
>> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
>> + return 0;
>> + else
>> + return pos & 0xffffffff;
>> +}
>> +
>> +/*
>> + * Return 32- or 64-bit end-of-file for dx directories
>> + */
>> +static inline loff_t ext3_get_htree_eof(struct file *filp)
>> +{
>> + if ((filp->f_mode & FMODE_32BITHASH) ||
>> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
>> + return EXT3_HTREE_EOF_32BIT;
>> + else
>> + return EXT3_HTREE_EOF_64BIT;
>> +}
>> +
>> +
>> +/*
>> + * ext3_dir_llseek() calls generic_file_llseek[_size]() to handle both
>> + * non-htree and htree directories, where the "offset" is in terms
>> + * of the filename hash value instead of the byte offset.
>> + *
>> + * Because we may return a 64-bit hash that is well beyond s_maxbytes,
>> + * we need to pass the max hash as the maximum allowable offset in
>> + * the htree directory case.
>> + *
>> + * NOTE: offsets obtained *before* ext3_set_inode_flag(dir, EXT3_INODE_INDEX)
>> + * will be invalid once the directory was converted into a dx directory
>> + */
>> +loff_t ext3_dir_llseek(struct file *file, loff_t offset, int origin)
>> +{
>> + struct inode *inode = file->f_mapping->host;
>> + int dx_dir = is_dx_dir(inode);
>> +
>> + if (likely(dx_dir))
>> + return generic_file_llseek_size(file, offset, origin,
>> + ext3_get_htree_eof(file));
>> + else
>> + return generic_file_llseek(file, offset, origin);
>> +}
>>
>> /*
>> * This structure holds the nodes of the red-black tree used to store
>> @@ -303,15 +367,16 @@ static void free_rb_tree_fname(struct rb_root *root)
>> }
>>
>>
>> -static struct dir_private_info *ext3_htree_create_dir_info(loff_t pos)
>> +static struct dir_private_info *ext3_htree_create_dir_info(struct file *filp,
>> + loff_t pos)
>> {
>> struct dir_private_info *p;
>>
>> p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
>> if (!p)
>> return NULL;
>> - p->curr_hash = pos2maj_hash(pos);
>> - p->curr_minor_hash = pos2min_hash(pos);
>> + p->curr_hash = pos2maj_hash(filp, pos);
>> + p->curr_minor_hash = pos2min_hash(filp, pos);
>> return p;
>> }
>>
>> @@ -401,7 +466,7 @@ static int call_filldir(struct file * filp, void * dirent,
>> printk("call_filldir: called with null fname?!?\n");
>> return 0;
>> }
>> - curr_pos = hash2pos(fname->hash, fname->minor_hash);
>> + curr_pos = hash2pos(filp, fname->hash, fname->minor_hash);
>> while (fname) {
>> error = filldir(dirent, fname->name,
>> fname->name_len, curr_pos,
>> @@ -426,13 +491,13 @@ static int ext3_dx_readdir(struct file * filp,
>> int ret;
>>
>> if (!info) {
>> - info = ext3_htree_create_dir_info(filp->f_pos);
>> + info = ext3_htree_create_dir_info(filp, filp->f_pos);
>> if (!info)
>> return -ENOMEM;
>> filp->private_data = info;
>> }
>>
>> - if (filp->f_pos == EXT3_HTREE_EOF)
>> + if (filp->f_pos == ext3_get_htree_eof(filp))
>> return 0; /* EOF */
>>
>> /* Some one has messed with f_pos; reset the world */
>> @@ -440,8 +505,8 @@ static int ext3_dx_readdir(struct file * filp,
>> free_rb_tree_fname(&info->root);
>> info->curr_node = NULL;
>> info->extra_fname = NULL;
>> - info->curr_hash = pos2maj_hash(filp->f_pos);
>> - info->curr_minor_hash = pos2min_hash(filp->f_pos);
>> + info->curr_hash = pos2maj_hash(filp, filp->f_pos);
>> + info->curr_minor_hash = pos2min_hash(filp, filp->f_pos);
>> }
>>
>> /*
>> @@ -473,7 +538,7 @@ static int ext3_dx_readdir(struct file * filp,
>> if (ret < 0)
>> return ret;
>> if (ret == 0) {
>> - filp->f_pos = EXT3_HTREE_EOF;
>> + filp->f_pos = ext3_get_htree_eof(filp);
>> break;
>> }
>> info->curr_node = rb_first(&info->root);
>> @@ -493,7 +558,7 @@ 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_HTREE_EOF;
>> + filp->f_pos = ext3_get_htree_eof(filp);
>> break;
>> }
>> info->curr_hash = info->next_hash;
>> @@ -512,3 +577,15 @@ static int ext3_release_dir (struct inode * inode, struct file * filp)
>>
>> return 0;
>> }
>> +
>> +const struct file_operations ext3_dir_operations = {
>> + .llseek = ext3_dir_llseek,
>> + .read = generic_read_dir,
>> + .readdir = ext3_readdir,
>> + .unlocked_ioctl = ext3_ioctl,
>> +#ifdef CONFIG_COMPAT
>> + .compat_ioctl = ext3_compat_ioctl,
>> +#endif
>> + .fsync = ext3_sync_file,
>> + .release = ext3_release_dir,
>> +};
>> diff --git a/fs/ext3/ext3.h b/fs/ext3/ext3.h
>> index b6515fd..fe5bef7 100644
>> --- a/fs/ext3/ext3.h
>> +++ b/fs/ext3/ext3.h
>> @@ -920,7 +920,11 @@ struct dx_hash_info
>> u32 *seed;
>> };
>>
>> -#define EXT3_HTREE_EOF 0x7fffffff
>> +
>> +/* 32 and 64 bit signed EOF for dx directories */
>> +#define EXT3_HTREE_EOF_32BIT ((1UL << (32 - 1)) - 1)
>> +#define EXT3_HTREE_EOF_64BIT ((1ULL << (64 - 1)) - 1)
>> +
>>
>> /*
>> * Control parameters used by ext3_htree_next_block
>> diff --git a/fs/ext3/hash.c b/fs/ext3/hash.c
>> index d10231d..ede315c 100644
>> --- a/fs/ext3/hash.c
>> +++ b/fs/ext3/hash.c
>> @@ -198,8 +198,8 @@ int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
>> return -1;
>> }
>> hash = hash & ~1;
>> - if (hash == (EXT3_HTREE_EOF << 1))
>> - hash = (EXT3_HTREE_EOF-1) << 1;
>> + if (hash == (EXT3_HTREE_EOF_32BIT << 1))
>> + hash = (EXT3_HTREE_EOF_32BIT - 1) << 1;
>> hinfo->hash = hash;
>> hinfo->minor_hash = minor_hash;
>> return 0;
>>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: ext3: return 32/64-bit dir name hash according to usage type
2012-04-26 18:10 ext3: return 32/64-bit dir name hash according to usage type Eric Sandeen
2012-04-26 18:26 ` J. Bruce Fields
@ 2012-04-26 18:57 ` Jan Kara
1 sibling, 0 replies; 4+ messages in thread
From: Jan Kara @ 2012-04-26 18:57 UTC (permalink / raw)
To: Eric Sandeen; +Cc: ext4 development, Jan Kara, Bruce Fields, Bernd Schubert
On Thu 26-04-12 13:10:39, Eric Sandeen wrote:
> This is based on commit d1f5273e9adb40724a85272f248f210dc4ce919a
> ext4: return 32/64-bit dir name hash according to usage type
> by Fan Yong <yong.fan@whamcloud.com>
>
> Traditionally ext2/3/4 has returned a 32-bit hash value from llseek()
> to appease NFSv2, which can only handle a 32-bit cookie for seekdir()
> and telldir(). However, this causes problems if there are 32-bit hash
> collisions, since the NFSv2 server can get stuck resending the same
> entries from the directory repeatedly.
>
> Allow ext3 to return a full 64-bit hash (both major and minor) for
> telldir to decrease the chance of hash collisions.
>
> This patch does implement a new ext3_dir_llseek op, because with 64-bit
> hashes, nfs will attempt to seek to a hash "offset" which is much
> larger than ext3's s_maxbytes. So for dx dirs, we call
> generic_file_llseek_size() with the appropriate max hash value as the
> maximum seekable size. Otherwise we just pass through to
> generic_file_llseek().
>
> Patch-updated-by: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
> Patch-updated-by: Eric Sandeen <sandeen@redhat.com>
> (blame us if something is not correct)
Thanks Eric. The patch looks good so I've added it to my tree.
Honza
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
>
> diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
> index cc761ad..92490e9 100644
> --- a/fs/ext3/dir.c
> +++ b/fs/ext3/dir.c
> @@ -21,30 +21,15 @@
> *
> */
>
> +#include <linux/compat.h>
> #include "ext3.h"
>
> 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_readdir(struct file *, void *, filldir_t);
> static int ext3_dx_readdir(struct file * filp,
> void * dirent, filldir_t filldir);
> -static int ext3_release_dir (struct inode * inode,
> - struct file * filp);
> -
> -const struct file_operations ext3_dir_operations = {
> - .llseek = generic_file_llseek,
> - .read = generic_read_dir,
> - .readdir = ext3_readdir, /* we take BKL. needed?*/
> - .unlocked_ioctl = ext3_ioctl,
> -#ifdef CONFIG_COMPAT
> - .compat_ioctl = ext3_compat_ioctl,
> -#endif
> - .fsync = ext3_sync_file, /* BKL held */
> - .release = ext3_release_dir,
> -};
> -
>
> static unsigned char get_dtype(struct super_block *sb, int filetype)
> {
> @@ -55,6 +40,25 @@ static unsigned char get_dtype(struct super_block *sb, int filetype)
> return (ext3_filetype_table[filetype]);
> }
>
> +/**
> + * Check if the given dir-inode refers to an htree-indexed directory
> + * (or a directory which chould potentially get coverted to use htree
> + * indexing).
> + *
> + * Return 1 if it is a dx dir, 0 if not
> + */
> +static int is_dx_dir(struct inode *inode)
> +{
> + struct super_block *sb = inode->i_sb;
> +
> + if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
> + EXT3_FEATURE_COMPAT_DIR_INDEX) &&
> + ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
> + ((inode->i_size >> sb->s_blocksize_bits) == 1)))
> + return 1;
> +
> + return 0;
> +}
>
> int ext3_check_dir_entry (const char * function, struct inode * dir,
> struct ext3_dir_entry_2 * de,
> @@ -94,18 +98,13 @@ static int ext3_readdir(struct file * filp,
> unsigned long offset;
> int i, stored;
> struct ext3_dir_entry_2 *de;
> - struct super_block *sb;
> int err;
> struct inode *inode = filp->f_path.dentry->d_inode;
> + struct super_block *sb = inode->i_sb;
> int ret = 0;
> int dir_has_error = 0;
>
> - sb = inode->i_sb;
> -
> - if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
> - EXT3_FEATURE_COMPAT_DIR_INDEX) &&
> - ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
> - ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
> + if (is_dx_dir(inode)) {
> err = ext3_dx_readdir(filp, dirent, filldir);
> if (err != ERR_BAD_DX_DIR) {
> ret = err;
> @@ -227,22 +226,87 @@ out:
> return ret;
> }
>
> +static inline int is_32bit_api(void)
> +{
> +#ifdef CONFIG_COMPAT
> + return is_compat_task();
> +#else
> + return (BITS_PER_LONG == 32);
> +#endif
> +}
> +
> /*
> * These functions convert from the major/minor hash to an f_pos
> - * value.
> + * value for dx directories
> *
> - * Currently we only use major hash numer. This is unfortunate, but
> - * on 32-bit machines, the same VFS interface is used for lseek and
> - * llseek, so if we use the 64 bit offset, then the 32-bit versions of
> - * lseek/telldir/seekdir will blow out spectacularly, and from within
> - * the ext2 low-level routine, we don't know if we're being called by
> - * a 64-bit version of the system call or the 32-bit version of the
> - * system call. Worse yet, NFSv2 only allows for a 32-bit readdir
> - * cookie. Sigh.
> + * Upper layer (for example NFS) should specify FMODE_32BITHASH or
> + * FMODE_64BITHASH explicitly. On the other hand, we allow ext3 to be mounted
> + * directly on both 32-bit and 64-bit nodes, under such case, neither
> + * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
> */
> -#define hash2pos(major, minor) (major >> 1)
> -#define pos2maj_hash(pos) ((pos << 1) & 0xffffffff)
> -#define pos2min_hash(pos) (0)
> +static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
> +{
> + if ((filp->f_mode & FMODE_32BITHASH) ||
> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
> + return major >> 1;
> + else
> + return ((__u64)(major >> 1) << 32) | (__u64)minor;
> +}
> +
> +static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
> +{
> + if ((filp->f_mode & FMODE_32BITHASH) ||
> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
> + return (pos << 1) & 0xffffffff;
> + else
> + return ((pos >> 32) << 1) & 0xffffffff;
> +}
> +
> +static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
> +{
> + if ((filp->f_mode & FMODE_32BITHASH) ||
> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
> + return 0;
> + else
> + return pos & 0xffffffff;
> +}
> +
> +/*
> + * Return 32- or 64-bit end-of-file for dx directories
> + */
> +static inline loff_t ext3_get_htree_eof(struct file *filp)
> +{
> + if ((filp->f_mode & FMODE_32BITHASH) ||
> + (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
> + return EXT3_HTREE_EOF_32BIT;
> + else
> + return EXT3_HTREE_EOF_64BIT;
> +}
> +
> +
> +/*
> + * ext3_dir_llseek() calls generic_file_llseek[_size]() to handle both
> + * non-htree and htree directories, where the "offset" is in terms
> + * of the filename hash value instead of the byte offset.
> + *
> + * Because we may return a 64-bit hash that is well beyond s_maxbytes,
> + * we need to pass the max hash as the maximum allowable offset in
> + * the htree directory case.
> + *
> + * NOTE: offsets obtained *before* ext3_set_inode_flag(dir, EXT3_INODE_INDEX)
> + * will be invalid once the directory was converted into a dx directory
> + */
> +loff_t ext3_dir_llseek(struct file *file, loff_t offset, int origin)
> +{
> + struct inode *inode = file->f_mapping->host;
> + int dx_dir = is_dx_dir(inode);
> +
> + if (likely(dx_dir))
> + return generic_file_llseek_size(file, offset, origin,
> + ext3_get_htree_eof(file));
> + else
> + return generic_file_llseek(file, offset, origin);
> +}
>
> /*
> * This structure holds the nodes of the red-black tree used to store
> @@ -303,15 +367,16 @@ static void free_rb_tree_fname(struct rb_root *root)
> }
>
>
> -static struct dir_private_info *ext3_htree_create_dir_info(loff_t pos)
> +static struct dir_private_info *ext3_htree_create_dir_info(struct file *filp,
> + loff_t pos)
> {
> struct dir_private_info *p;
>
> p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
> if (!p)
> return NULL;
> - p->curr_hash = pos2maj_hash(pos);
> - p->curr_minor_hash = pos2min_hash(pos);
> + p->curr_hash = pos2maj_hash(filp, pos);
> + p->curr_minor_hash = pos2min_hash(filp, pos);
> return p;
> }
>
> @@ -401,7 +466,7 @@ static int call_filldir(struct file * filp, void * dirent,
> printk("call_filldir: called with null fname?!?\n");
> return 0;
> }
> - curr_pos = hash2pos(fname->hash, fname->minor_hash);
> + curr_pos = hash2pos(filp, fname->hash, fname->minor_hash);
> while (fname) {
> error = filldir(dirent, fname->name,
> fname->name_len, curr_pos,
> @@ -426,13 +491,13 @@ static int ext3_dx_readdir(struct file * filp,
> int ret;
>
> if (!info) {
> - info = ext3_htree_create_dir_info(filp->f_pos);
> + info = ext3_htree_create_dir_info(filp, filp->f_pos);
> if (!info)
> return -ENOMEM;
> filp->private_data = info;
> }
>
> - if (filp->f_pos == EXT3_HTREE_EOF)
> + if (filp->f_pos == ext3_get_htree_eof(filp))
> return 0; /* EOF */
>
> /* Some one has messed with f_pos; reset the world */
> @@ -440,8 +505,8 @@ static int ext3_dx_readdir(struct file * filp,
> free_rb_tree_fname(&info->root);
> info->curr_node = NULL;
> info->extra_fname = NULL;
> - info->curr_hash = pos2maj_hash(filp->f_pos);
> - info->curr_minor_hash = pos2min_hash(filp->f_pos);
> + info->curr_hash = pos2maj_hash(filp, filp->f_pos);
> + info->curr_minor_hash = pos2min_hash(filp, filp->f_pos);
> }
>
> /*
> @@ -473,7 +538,7 @@ static int ext3_dx_readdir(struct file * filp,
> if (ret < 0)
> return ret;
> if (ret == 0) {
> - filp->f_pos = EXT3_HTREE_EOF;
> + filp->f_pos = ext3_get_htree_eof(filp);
> break;
> }
> info->curr_node = rb_first(&info->root);
> @@ -493,7 +558,7 @@ 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_HTREE_EOF;
> + filp->f_pos = ext3_get_htree_eof(filp);
> break;
> }
> info->curr_hash = info->next_hash;
> @@ -512,3 +577,15 @@ static int ext3_release_dir (struct inode * inode, struct file * filp)
>
> return 0;
> }
> +
> +const struct file_operations ext3_dir_operations = {
> + .llseek = ext3_dir_llseek,
> + .read = generic_read_dir,
> + .readdir = ext3_readdir,
> + .unlocked_ioctl = ext3_ioctl,
> +#ifdef CONFIG_COMPAT
> + .compat_ioctl = ext3_compat_ioctl,
> +#endif
> + .fsync = ext3_sync_file,
> + .release = ext3_release_dir,
> +};
> diff --git a/fs/ext3/ext3.h b/fs/ext3/ext3.h
> index b6515fd..fe5bef7 100644
> --- a/fs/ext3/ext3.h
> +++ b/fs/ext3/ext3.h
> @@ -920,7 +920,11 @@ struct dx_hash_info
> u32 *seed;
> };
>
> -#define EXT3_HTREE_EOF 0x7fffffff
> +
> +/* 32 and 64 bit signed EOF for dx directories */
> +#define EXT3_HTREE_EOF_32BIT ((1UL << (32 - 1)) - 1)
> +#define EXT3_HTREE_EOF_64BIT ((1ULL << (64 - 1)) - 1)
> +
>
> /*
> * Control parameters used by ext3_htree_next_block
> diff --git a/fs/ext3/hash.c b/fs/ext3/hash.c
> index d10231d..ede315c 100644
> --- a/fs/ext3/hash.c
> +++ b/fs/ext3/hash.c
> @@ -198,8 +198,8 @@ int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
> return -1;
> }
> hash = hash & ~1;
> - if (hash == (EXT3_HTREE_EOF << 1))
> - hash = (EXT3_HTREE_EOF-1) << 1;
> + if (hash == (EXT3_HTREE_EOF_32BIT << 1))
> + hash = (EXT3_HTREE_EOF_32BIT - 1) << 1;
> hinfo->hash = hash;
> hinfo->minor_hash = minor_hash;
> return 0;
>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-04-26 18:58 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2012-04-26 18:10 ext3: return 32/64-bit dir name hash according to usage type Eric Sandeen
2012-04-26 18:26 ` J. Bruce Fields
2012-04-26 18:28 ` Eric Sandeen
2012-04-26 18:57 ` Jan Kara
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