* This is to avoid polluting the dcache with short file names. We want them to
* work but we don't care for how quickly one can access them. This also fixes
* the dcache aliasing issues.
+ *
+ * Locking: - Caller must hold i_sem on the directory.
+ * - Each page cache page in the index allocation mapping must be
+ * locked whilst being accessed otherwise we may find a corrupt
+ * page due to it being under ->writepage at the moment which
+ * applies the mst protection fixups before writing out and then
+ * removes them again after the write is complete after which it
+ * unlocks the page.
*/
MFT_REF ntfs_lookup_inode_by_name(ntfs_inode *dir_ni, const ntfschar *uname,
const int uname_len, ntfs_name **res)
u8 *kaddr;
ntfs_name *name = NULL;
+ BUG_ON(!S_ISDIR(VFS_I(dir_ni)->i_mode));
+ BUG_ON(NInoAttr(dir_ni));
/* Get hold of the mft record for the directory. */
m = map_mft_record(dir_ni);
if (unlikely(IS_ERR(m))) {
err = PTR_ERR(page);
goto err_out;
}
+ lock_page(page);
kaddr = (u8*)page_address(page);
fast_descend_into_child_node:
/* Get to the index allocation block. */
*res = NULL;
}
mref = le64_to_cpu(ie->data.dir.indexed_file);
+ unlock_page(page);
ntfs_unmap_page(page);
return mref;
}
"this message to "
"linux-ntfs-dev@lists."
"sourceforge.net.");
+ unlock_page(page);
ntfs_unmap_page(page);
goto dir_err_out;
}
vol->cluster_size_bits >>
PAGE_CACHE_SHIFT)
goto fast_descend_into_child_node;
+ unlock_page(page);
ntfs_unmap_page(page);
goto descend_into_child_node;
}
* associated with it.
*/
if (name) {
+ unlock_page(page);
ntfs_unmap_page(page);
return name->mref;
}
ntfs_debug("Entry not found.");
err = -ENOENT;
unm_err_out:
+ unlock_page(page);
ntfs_unmap_page(page);
err_out:
if (ctx)
err = PTR_ERR(page);
goto err_out;
}
+ lock_page(page);
kaddr = (u8*)page_address(page);
fast_descend_into_child_node:
/* Get to the index allocation block. */
vol->upcase, vol->upcase_len)) {
found_it2:
mref = le64_to_cpu(ie->data.dir.indexed_file);
+ unlock_page(page);
ntfs_unmap_page(page);
return mref;
}
vol->cluster_size_bits >>
PAGE_CACHE_SHIFT)
goto fast_descend_into_child_node;
+ unlock_page(page);
ntfs_unmap_page(page);
goto descend_into_child_node;
}
ntfs_debug("Entry not found.");
err = -ENOENT;
unm_err_out:
+ unlock_page(page);
ntfs_unmap_page(page);
err_out:
if (ctx)
* @ndir: ntfs inode of current directory
* @index_type: specifies whether @iu is an index root or an index allocation
* @iu: index root or index allocation attribute to which @ie belongs
+ * @ia_page: page in which the index allocation buffer @ie is in resides
* @ie: current index entry
* @name: buffer to use for the converted name
* @dirent: vfs filldir callback context
*
* Convert the Unicode @name to the loaded NLS and pass it to the @filldir
* callback.
+ *
+ * If @index_type is INDEX_TYPE_ALLOCATION, @ia_page is the locked page
+ * containing the index allocation block containing the index entry @ie.
+ * Otherwise, @ia_page is NULL.
+ *
+ * Note, we drop (and then reacquire) the page lock on @ia_page across the
+ * @filldir() call otherwise we would deadlock with NFSd when it calls ->lookup
+ * since ntfs_lookup() will lock the same page. As an optimization, we do not
+ * retake the lock if we are returning a non-zero value as ntfs_readdir()
+ * would need to drop the lock immediately anyway.
*/
static inline int ntfs_filldir(ntfs_volume *vol, loff_t *fpos,
ntfs_inode *ndir, const INDEX_TYPE index_type,
- index_union iu, INDEX_ENTRY *ie, u8 *name,
- void *dirent, filldir_t filldir)
+ index_union iu, struct page *ia_page, INDEX_ENTRY *ie,
+ u8 *name, void *dirent, filldir_t filldir)
{
- int name_len;
+ unsigned long mref;
+ int name_len, rc;
unsigned dt_type;
FILE_NAME_TYPE_FLAGS name_type;
dt_type = DT_DIR;
else
dt_type = DT_REG;
+ mref = MREF_LE(ie->data.dir.indexed_file);
+ /*
+ * Drop the page lock otherwise we deadlock with NFS when it calls
+ * ->lookup since ntfs_lookup() will lock the same page.
+ */
+ if (index_type == INDEX_TYPE_ALLOCATION)
+ unlock_page(ia_page);
ntfs_debug("Calling filldir for %s with len %i, fpos 0x%llx, inode "
- "0x%lx, DT_%s.", name, name_len, *fpos,
- MREF_LE(ie->data.dir.indexed_file),
+ "0x%lx, DT_%s.", name, name_len, *fpos, mref,
dt_type == DT_DIR ? "DIR" : "REG");
- return filldir(dirent, name, name_len, *fpos,
- MREF_LE(ie->data.dir.indexed_file), dt_type);
+ rc = filldir(dirent, name, name_len, *fpos, mref, dt_type);
+ /* Relock the page but not if we are aborting ->readdir. */
+ if (!rc && index_type == INDEX_TYPE_ALLOCATION)
+ lock_page(ia_page);
+ return rc;
}
/*
- * VFS calls readdir without BKL but with i_sem held. This protects the VFS
- * parts (e.g. ->f_pos and ->i_size, and it also protects against directory
- * modifications).
- *
* We use the same basic approach as the old NTFS driver, i.e. we parse the
* index root entries and then the index allocation entries that are marked
* as in use in the index bitmap.
+ *
* While this will return the names in random order this doesn't matter for
- * readdir but OTOH results in a faster readdir.
+ * ->readdir but OTOH results in a faster ->readdir.
+ *
+ * VFS calls ->readdir without BKL but with i_sem held. This protects the VFS
+ * parts (e.g. ->f_pos and ->i_size, and it also protects against directory
+ * modifications).
+ *
+ * Locking: - Caller must hold i_sem on the directory.
+ * - Each page cache page in the index allocation mapping must be
+ * locked whilst being accessed otherwise we may find a corrupt
+ * page due to it being under ->writepage at the moment which
+ * applies the mst protection fixups before writing out and then
+ * removes them again after the write is complete after which it
+ * unlocks the page.
*/
static int ntfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
* or signals an error (both covered by the rc test).
*/
for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
- ntfs_debug("In index root, offset 0x%x.", (u8*)ie - (u8*)ir);
+ ntfs_debug("In index root, offset 0x%zx.", (u8*)ie - (u8*)ir);
/* Bounds checks. */
if (unlikely((u8*)ie < (u8*)ir || (u8*)ie +
sizeof(INDEX_ENTRY_HEADER) > index_end ||
if (ir_pos > (u8*)ie - (u8*)ir)
continue;
/* Submit the name to the filldir callback. */
- rc = ntfs_filldir(vol, &fpos, ndir, INDEX_TYPE_ROOT, ir, ie,
- name, dirent, filldir);
+ rc = ntfs_filldir(vol, &fpos, ndir, INDEX_TYPE_ROOT, ir, NULL,
+ ie, name, dirent, filldir);
if (rc) {
kfree(ir);
goto abort;
/* If the current index buffer is in the same page we reuse the page. */
if ((prev_ia_pos & PAGE_CACHE_MASK) != (ia_pos & PAGE_CACHE_MASK)) {
prev_ia_pos = ia_pos;
- if (likely(ia_page != NULL))
+ if (likely(ia_page != NULL)) {
+ unlock_page(ia_page);
ntfs_unmap_page(ia_page);
+ }
/*
* Map the page cache page containing the current ia_pos,
* reading it from disk if necessary.
ia_page = NULL;
goto err_out;
}
+ lock_page(ia_page);
kaddr = (u8*)page_address(ia_page);
}
/* Get the current index buffer. */
/* Skip index block entry if continuing previous readdir. */
if (ia_pos - ia_start > (u8*)ie - (u8*)ia)
continue;
- /* Submit the name to the filldir callback. */
+ /*
+ * Submit the name to the @filldir callback. Note,
+ * ntfs_filldir() drops the lock on @ia_page but it retakes it
+ * before returning, unless a non-zero value is returned in
+ * which case the page is left unlocked.
+ */
rc = ntfs_filldir(vol, &fpos, ndir, INDEX_TYPE_ALLOCATION, ia,
- ie, name, dirent, filldir);
+ ia_page, ie, name, dirent, filldir);
if (rc) {
+ /* @ia_page is already unlocked in this case. */
ntfs_unmap_page(ia_page);
ntfs_unmap_page(bmp_page);
goto abort;
}
goto find_next_index_buffer;
unm_EOD:
- if (ia_page)
+ if (ia_page) {
+ unlock_page(ia_page);
ntfs_unmap_page(ia_page);
+ }
ntfs_unmap_page(bmp_page);
EOD:
/* We are finished, set fpos to EOD. */
err_out:
if (bmp_page)
ntfs_unmap_page(bmp_page);
- if (ia_page)
+ if (ia_page) {
+ unlock_page(ia_page);
ntfs_unmap_page(ia_page);
+ }
if (ir)
kfree(ir);
if (name)
git://git.onelab.eu / linux-2.6.git / blobdiff