From: Miklos Szeredi <mszer...@suse.cz>

Implement RENAME_EXCHANGE flag in renameat2 syscall.

Signed-off-by: Miklos Szeredi <mszer...@suse.cz>
---
 fs/ext4/namei.c | 103 +++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 73 insertions(+), 30 deletions(-)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index fb0f1db..6d87a09 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3141,8 +3141,9 @@ static void ext4_rename_delete(handle_t *handle, struct 
ext4_renament *ent)
  * while new_{dentry,inode) refers to the destination dentry/inode
  * This comes from rename(const char *oldpath, const char *newpath)
  */
-static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
-                      struct inode *new_dir, struct dentry *new_dentry)
+static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
+                       struct inode *new_dir, struct dentry *new_dentry,
+                       unsigned int flags)
 {
        handle_t *handle = NULL;
        struct ext4_renament old = {
@@ -3154,16 +3155,18 @@ static int ext4_rename(struct inode *old_dir, struct 
dentry *old_dentry,
                .dentry = new_dentry,
        };
        int retval;
+       bool overwrite = !(flags & RENAME_EXCHANGE);
 
        dquot_initialize(old.dir);
        dquot_initialize(new.dir);
 
        /* Initialize quotas before so that eventual writes go
         * in separate transaction */
-       if (new.dentry->d_inode)
+       if (overwrite && new.dentry->d_inode)
                dquot_initialize(new.dentry->d_inode);
 
-       old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
+       old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
+                                &old.de, &old.inlined);
        /*
         *  Check for inode number is _not_ due to possible IO errors.
         *  We might rmdir the source, keep it as pwd of some process
@@ -3178,18 +3181,22 @@ static int ext4_rename(struct inode *old_dir, struct 
dentry *old_dentry,
        new.inode = new.dentry->d_inode;
        new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
                                 &new.de, &new.inlined);
-       if (new.bh) {
-               if (!new.inode) {
-                       brelse(new.bh);
-                       new.bh = NULL;
+       if (overwrite) {
+               if (new.bh) {
+                       if (!new.inode) {
+                               brelse(new.bh);
+                               new.bh = NULL;
+                       }
                }
+               if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
+                       ext4_alloc_da_blocks(old.inode);
+       } else if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino) {
+               goto end_rename;
        }
-       if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
-               ext4_alloc_da_blocks(old.inode);
 
        handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
                (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
-                EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
+                2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
        if (IS_ERR(handle))
                return PTR_ERR(handle);
 
@@ -3197,11 +3204,12 @@ static int ext4_rename(struct inode *old_dir, struct 
dentry *old_dentry,
                ext4_handle_sync(handle);
 
        if (S_ISDIR(old.inode->i_mode)) {
-               if (new.inode) {
+               if (overwrite && new.inode) {
                        retval = -ENOTEMPTY;
                        if (!empty_dir(new.inode))
                                goto end_rename;
-               } else {
+               }
+               if (!new.inode || !S_ISDIR(new.inode->i_mode)) {
                        retval = -EMLINK;
                        if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
                                goto end_rename;
@@ -3210,15 +3218,34 @@ static int ext4_rename(struct inode *old_dir, struct 
dentry *old_dentry,
                if (retval)
                        goto end_rename;
        }
+       if (!overwrite && S_ISDIR(new.inode->i_mode)) {
+               if (!S_ISDIR(old.inode->i_mode)) {
+                       retval = -EMLINK;
+                       if (new.dir != old.dir && EXT4_DIR_LINK_MAX(old.dir))
+                               goto end_rename;
+               }
+               retval = ext4_rename_dir_prepare(handle, &new);
+               if (retval)
+                       goto end_rename;
+       }
+
        if (!new.bh) {
                retval = ext4_add_entry(handle, new.dentry, old.inode);
                if (retval)
                        goto end_rename;
        } else {
+               u8 new_file_type = new.de->file_type;
                retval = ext4_setent(handle, &new,
                                     old.inode->i_ino, old.de->file_type);
                if (retval)
                        goto end_rename;
+
+               if (!overwrite) {
+                       retval = ext4_setent(handle, &old,
+                                            new.inode->i_ino, new_file_type);
+                       if (retval)
+                               goto end_rename;
+               }
        }
 
        /*
@@ -3228,35 +3255,51 @@ static int ext4_rename(struct inode *old_dir, struct 
dentry *old_dentry,
        old.inode->i_ctime = ext4_current_time(old.inode);
        ext4_mark_inode_dirty(handle, old.inode);
 
-       /*
-        * ok, that's it
-        */
-       ext4_rename_delete(handle, &old);
+       if (overwrite) {
+               /*
+                * ok, that's it
+                */
+               ext4_rename_delete(handle, &old);
 
-       if (new.inode) {
-               ext4_dec_count(handle, new.inode);
-               new.inode->i_ctime = ext4_current_time(new.inode);
+               old.dir->i_ctime = old.dir->i_mtime = 
ext4_current_time(old.dir);
+               ext4_update_dx_flag(old.dir);
        }
-       old.dir->i_ctime = old.dir->i_mtime = ext4_current_time(old.dir);
-       ext4_update_dx_flag(old.dir);
+       /* S_ISDIR(old.inode->i_mode */
        if (old.dir_bh) {
                retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
                if (retval)
                        goto end_rename;
 
-               ext4_dec_count(handle, old.dir);
-               if (new.inode) {
-                       /* checked empty_dir above, can't have another parent,
-                        * ext4_dec_count() won't work for many-linked dirs */
-                       clear_nlink(new.inode);
-               } else {
+               if (overwrite || !S_ISDIR(new.inode->i_mode))
+                       ext4_dec_count(handle, old.dir);
+
+               if (!new.inode || !S_ISDIR(new.inode->i_mode)) {
                        ext4_inc_count(handle, new.dir);
                        ext4_update_dx_flag(new.dir);
                        ext4_mark_inode_dirty(handle, new.dir);
                }
        }
+       /* !overwrite && S_ISDIR(new.inode->i_mode */
+       if (new.dir_bh) {
+               retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
+               if (retval)
+                       goto end_rename;
+
+               if (!S_ISDIR(old.inode->i_mode)) {
+                       ext4_dec_count(handle, new.dir);
+                       ext4_inc_count(handle, old.dir);
+                       ext4_mark_inode_dirty(handle, new.dir);
+               }
+       }
        ext4_mark_inode_dirty(handle, old.dir);
-       if (new.inode) {
+       if (overwrite && new.inode) {
+               ext4_dec_count(handle, new.inode);
+               new.inode->i_ctime = ext4_current_time(new.inode);
+               if (S_ISDIR(old.inode->i_mode)) {
+                       /* checked empty_dir above, can't have another parent,
+                        * ext4_dec_count() won't work for many-linked dirs */
+                       clear_nlink(new.inode);
+               }
                ext4_mark_inode_dirty(handle, new.inode);
                if (!new.inode->i_nlink)
                        ext4_orphan_add(handle, new.inode);
@@ -3285,7 +3328,7 @@ const struct inode_operations ext4_dir_inode_operations = 
{
        .rmdir          = ext4_rmdir,
        .mknod          = ext4_mknod,
        .tmpfile        = ext4_tmpfile,
-       .rename         = ext4_rename,
+       .rename2        = ext4_rename2,
        .setattr        = ext4_setattr,
        .setxattr       = generic_setxattr,
        .getxattr       = generic_getxattr,
-- 
1.8.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to