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From: Valerie Aurora on 8 Aug 2010 12:10
From: Jan Blunck <jblunck(a)suse.de>

The ext2_append_link() is later used to find or append a directory
entry to whiteout.

Signed-off-by: Jan Blunck <jblunck(a)suse.de>
Signed-off-by: Valerie Aurora <vaurora(a)redhat.com>
Cc: Theodore Tso <tytso(a)mit.edu>
Cc: linux-ext4(a)vger.kernel.org
---
fs/ext2/dir.c | 70 ++++++++++++++++++++++++++++++++++++++++----------------
1 files changed, 50 insertions(+), 20 deletions(-)

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index 7516957..57207a9 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -472,9 +472,10 @@ void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
}

/*
- * Parent is locked.
+ * Find or append a given dentry to the parent directory
*/
-int ext2_add_link (struct dentry *dentry, struct inode *inode)
+static ext2_dirent * ext2_append_entry(struct dentry * dentry,
+ struct page ** page)
{
struct inode *dir = dentry->d_parent->d_inode;
const char *name = dentry->d_name.name;
@@ -482,13 +483,10 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode)
unsigned chunk_size = ext2_chunk_size(dir);
unsigned reclen = EXT2_DIR_REC_LEN(namelen);
unsigned short rec_len, name_len;
- struct page *page = NULL;
- ext2_dirent * de;
+ ext2_dirent * de = NULL;
unsigned long npages = dir_pages(dir);
unsigned long n;
char *kaddr;
- loff_t pos;
- int err;

/*
* We take care of directory expansion in the same loop.
@@ -498,20 +496,19 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode)
for (n = 0; n <= npages; n++) {
char *dir_end;

- page = ext2_get_page(dir, n, 0);
- err = PTR_ERR(page);
- if (IS_ERR(page))
+ *page = ext2_get_page(dir, n, 0);
+ de = ERR_PTR(PTR_ERR(*page));
+ if (IS_ERR(*page))
goto out;
- lock_page(page);
- kaddr = page_address(page);
+ lock_page(*page);
+ kaddr = page_address(*page);
dir_end = kaddr + ext2_last_byte(dir, n);
de = (ext2_dirent *)kaddr;
kaddr += PAGE_CACHE_SIZE - reclen;
while ((char *)de <= kaddr) {
if ((char *)de == dir_end) {
/* We hit i_size */
- name_len = 0;
- rec_len = chunk_size;
+ de->name_len = 0;
de->rec_len = ext2_rec_len_to_disk(chunk_size);
de->inode = 0;
goto got_it;
@@ -519,12 +516,11 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode)
if (de->rec_len == 0) {
ext2_error(dir->i_sb, __func__,
"zero-length directory entry");
- err = -EIO;
+ de = ERR_PTR(-EIO);
goto out_unlock;
}
- err = -EEXIST;
if (ext2_match (namelen, name, de))
- goto out_unlock;
+ goto got_it;
name_len = EXT2_DIR_REC_LEN(de->name_len);
rec_len = ext2_rec_len_from_disk(de->rec_len);
if (!de->inode && rec_len >= reclen)
@@ -533,13 +529,48 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode)
goto got_it;
de = (ext2_dirent *) ((char *) de + rec_len);
}
- unlock_page(page);
- ext2_put_page(page);
+ unlock_page(*page);
+ ext2_put_page(*page);
}
+
BUG();
- return -EINVAL;

got_it:
+ return de;
+ /* OFFSET_CACHE */
+out_unlock:
+ unlock_page(*page);
+ ext2_put_page(*page);
+out:
+ return de;
+}
+
+/*
+ * Parent is locked.
+ */
+int ext2_add_link (struct dentry *dentry, struct inode *inode)
+{
+ struct inode *dir = dentry->d_parent->d_inode;
+ const char *name = dentry->d_name.name;
+ int namelen = dentry->d_name.len;
+ unsigned short rec_len, name_len;
+ ext2_dirent * de;
+ struct page *page;
+ loff_t pos;
+ int err;
+
+ de = ext2_append_entry(dentry, &page);
+ if (IS_ERR(de))
+ return PTR_ERR(de);
+
+ err = -EEXIST;
+ if (ext2_match (namelen, name, de))
+ goto out_unlock;
+
+got_it:
+ name_len = EXT2_DIR_REC_LEN(de->name_len);
+ rec_len = ext2_rec_len_from_disk(de->rec_len);
+
pos = page_offset(page) +
(char*)de - (char*)page_address(page);
err = __ext2_write_begin(NULL, page->mapping, pos, rec_len, 0,
@@ -563,7 +594,6 @@ got_it:
/* OFFSET_CACHE */
out_put:
ext2_put_page(page);
-out:
return err;
out_unlock:
unlock_page(page);
--
1.6.3.3

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Prev: [PATCH 15/39] union-mount: Introduce MNT_UNION and MS_UNION flags
Next: [PATCH 00/39] Union mounts - return d_ino from lower fs