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Subject[PATCH V3 12/21] ext4: Let ext4_readdir handle inline data.
Date
From: Tao Ma <boyu.mt@taobao.com>

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
---
fs/ext4/dir.c | 23 ++++------
fs/ext4/ext4.h | 12 +++++
fs/ext4/inline.c | 124 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ext4/xattr.h | 7 +++
4 files changed, 153 insertions(+), 13 deletions(-)

diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 6c2199e..691548c 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -27,10 +27,7 @@
#include <linux/slab.h>
#include <linux/rbtree.h>
#include "ext4.h"
-
-static unsigned char ext4_filetype_table[] = {
- DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
-};
+#include "xattr.h"

static int ext4_readdir(struct file *, void *, filldir_t);
static int ext4_dx_readdir(struct file *filp,
@@ -51,19 +48,13 @@ const struct file_operations ext4_dir_operations = {
};


-static unsigned char get_dtype(struct super_block *sb, int filetype)
-{
- if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) ||
- (filetype >= EXT4_FT_MAX))
- return DT_UNKNOWN;
-
- return (ext4_filetype_table[filetype]);
-}
-
/*
* Return 0 if the directory entry is OK, and 1 if there is a problem
*
* Note: this is the opposite of what ext2 and ext3 historically returned...
+ *
+ * bh passed here can be an inode block or a dir data block, depending
+ * on the inode inline data flag.
*/
int __ext4_check_dir_entry(const char *function, unsigned int line,
struct inode *dir, struct file *filp,
@@ -122,6 +113,12 @@ static int ext4_readdir(struct file *filp,

sb = inode->i_sb;

+ if (ext4_has_inline_data(inode)) {
+ ret = ext4_read_inline_dir(filp, dirent, filldir);
+ if (ret > 0 || ret < 0)
+ return ret;
+ }
+
if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
EXT4_FEATURE_COMPAT_DIR_INDEX) &&
((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index e61c967..25d6e58 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1832,6 +1832,18 @@ static inline void ext4_update_dx_flag(struct inode *inode)
EXT4_FEATURE_COMPAT_DIR_INDEX))
ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
}
+static unsigned char ext4_filetype_table[] = {
+ DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
+};
+
+static inline unsigned char get_dtype(struct super_block *sb, int filetype)
+{
+ if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) ||
+ (filetype >= EXT4_FT_MAX))
+ return DT_UNKNOWN;
+
+ return ext4_filetype_table[filetype];
+}

/* fsync.c */
extern int ext4_sync_file(struct file *, loff_t, loff_t, int);
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index db70d3e..0a41d64 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1176,6 +1176,130 @@ out:
}

/*
+ * Get the inline dentry at offset.
+ */
+static inline struct ext4_dir_entry_2 *
+ext4_get_inline_entry(struct inode *inode,
+ struct ext4_iloc *iloc,
+ unsigned int offset,
+ void **inline_start,
+ int *inline_size)
+{
+ void *inline_pos;
+
+ BUG_ON(offset > ext4_get_inline_size(inode));
+
+ if (offset < EXT4_MIN_INLINE_DATA_SIZE) {
+ inline_pos = ext4_raw_inode(iloc)->i_block;
+ *inline_size = EXT4_MIN_INLINE_DATA_SIZE;
+ } else {
+ inline_pos = ext4_get_inline_xattr_pos(inode, iloc);
+ offset -= EXT4_MIN_INLINE_DATA_SIZE;
+ *inline_size = ext4_get_inline_size(inode) -
+ EXT4_MIN_INLINE_DATA_SIZE;
+ }
+
+ if (inline_start)
+ *inline_start = inline_pos;
+ return (struct ext4_dir_entry_2 *)(inline_pos + offset);
+}
+
+int ext4_read_inline_dir(struct file *filp,
+ void *dirent, filldir_t filldir)
+{
+ int error = 0;
+ unsigned int offset;
+ int i, stored;
+ void *inline_pos;
+ struct ext4_dir_entry_2 *de;
+ struct super_block *sb;
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ int ret, inline_size = 0;
+ struct ext4_iloc iloc;
+
+ ret = ext4_get_inode_loc(inode, &iloc);
+ if (ret)
+ return ret;
+
+ down_read(&EXT4_I(inode)->xattr_sem);
+ if (!ext4_has_inline_data(inode))
+ goto out;
+
+ sb = inode->i_sb;
+ stored = 0;
+ offset = filp->f_pos & (sb->s_blocksize - 1);
+
+ while (!error && !stored && filp->f_pos < inode->i_size) {
+revalidate:
+ /* If the version 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) {
+ for (i = 0; i < inode->i_size && i < offset; ) {
+ de = ext4_get_inline_entry(inode, &iloc, i,
+ NULL, &inline_size);
+ /* It's too expensive to do a full
+ * dirent test each time round this
+ * loop, but we do have to test at
+ * least that it is non-zero. A
+ * failure will be detected in the
+ * dirent test below. */
+ if (ext4_rec_len_from_disk(de->rec_len,
+ inline_size) < EXT4_DIR_REC_LEN(1))
+ break;
+ i += ext4_rec_len_from_disk(de->rec_len,
+ inline_size);
+ }
+ offset = i;
+ filp->f_pos = offset;
+ filp->f_version = inode->i_version;
+ }
+
+ while (!error && filp->f_pos < inode->i_size) {
+ de = ext4_get_inline_entry(inode, &iloc, offset,
+ &inline_pos, &inline_size);
+ if (ext4_check_dir_entry(inode, filp, de,
+ iloc.bh, inline_pos,
+ inline_size, offset)) {
+ ret = stored;
+ goto out;
+ }
+ offset += ext4_rec_len_from_disk(de->rec_len,
+ inline_size);
+ 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++;
+ }
+ filp->f_pos += ext4_rec_len_from_disk(de->rec_len,
+ inline_size);
+ }
+ offset = 0;
+ }
+out:
+ up_read(&EXT4_I(inode)->xattr_sem);
+ brelse(iloc.bh);
+ return ret;
+}
+
+/*
* Try to create the inline data for the new dir.
* If it succeeds, return 0, otherwise return the error.
* In case of ENOSPC, the caller should create the normal disk layout dir.
diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
index 0229a78..e9e23ba 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -166,6 +166,8 @@ extern int ext4_try_add_inline_entry(handle_t *handle, struct dentry *dentry,
extern int ext4_try_create_inline_dir(handle_t *handle,
struct inode *parent,
struct inode *inode);
+extern int ext4_read_inline_dir(struct file *filp,
+ void *dirent, filldir_t filldir);
# else /* CONFIG_EXT4_FS_XATTR */

static inline int
@@ -343,6 +345,11 @@ static inline int ext4_try_create_inline_dir(handle_t *handle,
{
return 0;
}
+static inline int ext4_read_inline_dir(struct file *filp,
+ void *dirent, filldir_t filldir)
+{
+ return 0;
+}
# endif /* CONFIG_EXT4_FS_XATTR */

#ifdef CONFIG_EXT4_FS_SECURITY
--
1.7.0.4


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