linux/fs/ext4/symlink.c
Linus Torvalds d857da7b70 A very large number of cleanups and bug fixes --- in particular for
the ext4 encryption patches, which is a new feature added in the last
 merge window.  Also fix a number of long-standing xfstest failures.
 (Quota writes failing due to ENOSPC, a race between truncate and
 writepage in data=journalled mode that was causing generic/068 to
 fail, and other corner cases.)
 
 Also add support for FALLOC_FL_INSERT_RANGE, and improve jbd2
 performance eliminating locking when a buffer is modified more than
 once during a transaction (which is very common for allocation
 bitmaps, for example), in which case the state of the journalled
 buffer head doesn't need to change.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "A very large number of cleanups and bug fixes --- in particular for
  the ext4 encryption patches, which is a new feature added in the last
  merge window.  Also fix a number of long-standing xfstest failures.
  (Quota writes failing due to ENOSPC, a race between truncate and
  writepage in data=journalled mode that was causing generic/068 to
  fail, and other corner cases.)

  Also add support for FALLOC_FL_INSERT_RANGE, and improve jbd2
  performance eliminating locking when a buffer is modified more than
  once during a transaction (which is very common for allocation
  bitmaps, for example), in which case the state of the journalled
  buffer head doesn't need to change"

[ I renamed "ext4_follow_link()" to "ext4_encrypted_follow_link()" in
  the merge resolution, to make it clear that that function is _only_
  used for encrypted symlinks.  The function doesn't actually work for
  non-encrypted symlinks at all, and they use the generic helpers
                                         - Linus ]

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (52 commits)
  ext4: set lazytime on remount if MS_LAZYTIME is set by mount
  ext4: only call ext4_truncate when size <= isize
  ext4: make online defrag error reporting consistent
  ext4: minor cleanup of ext4_da_reserve_space()
  ext4: don't retry file block mapping on bigalloc fs with non-extent file
  ext4: prevent ext4_quota_write() from failing due to ENOSPC
  ext4: call sync_blockdev() before invalidate_bdev() in put_super()
  jbd2: speedup jbd2_journal_dirty_metadata()
  jbd2: get rid of open coded allocation retry loop
  ext4: improve warning directory handling messages
  jbd2: fix ocfs2 corrupt when updating journal superblock fails
  ext4: mballoc: avoid 20-argument function call
  ext4: wait for existing dio workers in ext4_alloc_file_blocks()
  ext4: recalculate journal credits as inode depth changes
  jbd2: use GFP_NOFS in jbd2_cleanup_journal_tail()
  ext4: use swap() in mext_page_double_lock()
  ext4: use swap() in memswap()
  ext4: fix race between truncate and __ext4_journalled_writepage()
  ext4 crypto: fail the mount if blocksize != pagesize
  ext4: Add support FALLOC_FL_INSERT_RANGE for fallocate
  ...
2015-06-25 14:06:55 -07:00

124 lines
3.1 KiB
C

/*
* linux/fs/ext4/symlink.c
*
* Only fast symlinks left here - the rest is done by generic code. AV, 1999
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/symlink.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* ext4 symlink handling code
*/
#include <linux/fs.h>
#include <linux/namei.h>
#include "ext4.h"
#include "xattr.h"
#ifdef CONFIG_EXT4_FS_ENCRYPTION
static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cookie)
{
struct page *cpage = NULL;
char *caddr, *paddr = NULL;
struct ext4_str cstr, pstr;
struct inode *inode = d_inode(dentry);
struct ext4_encrypted_symlink_data *sd;
loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
int res;
u32 plen, max_size = inode->i_sb->s_blocksize;
res = ext4_get_encryption_info(inode);
if (res)
return ERR_PTR(res);
if (ext4_inode_is_fast_symlink(inode)) {
caddr = (char *) EXT4_I(inode)->i_data;
max_size = sizeof(EXT4_I(inode)->i_data);
} else {
cpage = read_mapping_page(inode->i_mapping, 0, NULL);
if (IS_ERR(cpage))
return ERR_CAST(cpage);
caddr = kmap(cpage);
caddr[size] = 0;
}
/* Symlink is encrypted */
sd = (struct ext4_encrypted_symlink_data *)caddr;
cstr.name = sd->encrypted_path;
cstr.len = le32_to_cpu(sd->len);
if ((cstr.len +
sizeof(struct ext4_encrypted_symlink_data) - 1) >
max_size) {
/* Symlink data on the disk is corrupted */
res = -EIO;
goto errout;
}
plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ?
EXT4_FNAME_CRYPTO_DIGEST_SIZE*2 : cstr.len;
paddr = kmalloc(plen + 1, GFP_NOFS);
if (!paddr) {
res = -ENOMEM;
goto errout;
}
pstr.name = paddr;
pstr.len = plen;
res = _ext4_fname_disk_to_usr(inode, NULL, &cstr, &pstr);
if (res < 0)
goto errout;
/* Null-terminate the name */
if (res <= plen)
paddr[res] = '\0';
if (cpage) {
kunmap(cpage);
page_cache_release(cpage);
}
return *cookie = paddr;
errout:
if (cpage) {
kunmap(cpage);
page_cache_release(cpage);
}
kfree(paddr);
return ERR_PTR(res);
}
const struct inode_operations ext4_encrypted_symlink_inode_operations = {
.readlink = generic_readlink,
.follow_link = ext4_encrypted_follow_link,
.put_link = kfree_put_link,
.setattr = ext4_setattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = ext4_listxattr,
.removexattr = generic_removexattr,
};
#endif
const struct inode_operations ext4_symlink_inode_operations = {
.readlink = generic_readlink,
.follow_link = page_follow_link_light,
.put_link = page_put_link,
.setattr = ext4_setattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = ext4_listxattr,
.removexattr = generic_removexattr,
};
const struct inode_operations ext4_fast_symlink_inode_operations = {
.readlink = generic_readlink,
.follow_link = simple_follow_link,
.setattr = ext4_setattr,
.setxattr = generic_setxattr,
.getxattr = generic_getxattr,
.listxattr = ext4_listxattr,
.removexattr = generic_removexattr,
};