Commit c0c1cc0e authored by Anton Altaparmakov's avatar Anton Altaparmakov

NTFS: - Fix bug in fs/ntfs/attrib.c::ntfs_find_vcn_nolock() where after

        dropping the read lock and taking the write lock we were not checking
        whether someone else did not already do the work we wanted to do.
      - Rename ntfs_find_vcn_nolock() to ntfs_attr_find_vcn_nolock().
      - Tidy up some comments in fs/ntfs/runlist.c.
      - Add LCN_ENOMEM and LCN_EIO definitions to fs/ntfs/runlist.h.
Signed-off-by: default avatarAnton Altaparmakov <aia21@cantab.net>
parent 271849a9
......@@ -92,6 +92,11 @@ ToDo/Notes:
non-resident in fs/ntfs/attrib.c::ntfs_attr_can_be_non_resident().
- Add fs/ntfs/attrib.c::ntfs_attr_vcn_to_lcn_nolock() used by the new
write code.
- Fix bug in fs/ntfs/attrib.c::ntfs_find_vcn_nolock() where after
dropping the read lock and taking the write lock we were not checking
whether someone else did not already do the work we wanted to do.
- Rename fs/ntfs/attrib.c::ntfs_find_vcn_nolock() to
ntfs_attr_find_vcn_nolock() and update all callers.
2.1.22 - Many bug and race fixes and error handling improvements.
......
......@@ -193,19 +193,19 @@ retry_remap:
}
/**
* ntfs_find_vcn_nolock - find a vcn in the runlist described by an ntfs inode
* ntfs_attr_find_vcn_nolock - find a vcn in the runlist of an ntfs inode
* @ni: ntfs inode describing the runlist to search
* @vcn: vcn to find
* @write_locked: true if the runlist is locked for writing
*
* Find the virtual cluster number @vcn in the runlist described by the ntfs
* inode @ni and return the address of the runlist element containing the @vcn.
* The runlist is left locked and the caller has to unlock it. In the error
* case, the runlist is left in the same locking state as on entry.
*
* Note if @write_locked is FALSE the lock may be dropped inside the function
* so you cannot rely on the runlist still being the same when this function
* returns.
* If the @vcn is not mapped yet, the attempt is made to map the attribute
* extent containing the @vcn and the vcn to lcn conversion is retried.
*
* If @write_locked is true the caller has locked the runlist for writing and
* if false for reading.
*
* Note you need to distinguish between the lcn of the returned runlist element
* being >= 0 and LCN_HOLE. In the later case you have to return zeroes on
......@@ -221,13 +221,12 @@ retry_remap:
* -ENOMEM - Not enough memory to map runlist.
* -EIO - Critical error (runlist/file is corrupt, i/o error, etc).
*
* Locking: - The runlist must be unlocked on entry.
* - On failing return, the runlist is unlocked.
* - On successful return, the runlist is locked. If @need_write us
* true, it is locked for writing. Otherwise is is locked for
* reading.
* Locking: - The runlist must be locked on entry and is left locked on return.
* - If @write_locked is FALSE, i.e. the runlist is locked for reading,
* the lock may be dropped inside the function so you cannot rely on
* the runlist still being the same when this function returns.
*/
runlist_element *ntfs_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
const BOOL write_locked)
{
runlist_element *rl;
......@@ -268,6 +267,12 @@ retry_remap:
if (!write_locked) {
up_read(&ni->runlist.lock);
down_write(&ni->runlist.lock);
if (unlikely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) !=
LCN_RL_NOT_MAPPED)) {
up_write(&ni->runlist.lock);
down_read(&ni->runlist.lock);
goto retry_remap;
}
}
err = ntfs_map_runlist_nolock(ni, vcn);
if (!write_locked) {
......
......@@ -66,8 +66,8 @@ extern int ntfs_map_runlist(ntfs_inode *ni, VCN vcn);
extern LCN ntfs_attr_vcn_to_lcn_nolock(ntfs_inode *ni, const VCN vcn,
const BOOL write_locked);
extern runlist_element *ntfs_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
const BOOL write_locked);
extern runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni,
const VCN vcn, const BOOL write_locked);
int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name,
const u32 name_len, const IGNORE_CASE_BOOL ic,
......
......@@ -850,7 +850,7 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
/* This returns with ni->runlist locked for reading on success. */
down_read(&ni->runlist.lock);
rl = ntfs_find_vcn_nolock(ni, start_vcn, FALSE);
rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, FALSE);
if (IS_ERR(rl)) {
if (!is_rollback)
ntfs_error(vol->sb, "Failed to find first runlist "
......@@ -904,7 +904,7 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
/* Attempt to map runlist. */
vcn = rl->vcn;
rl = ntfs_find_vcn_nolock(ni, vcn, FALSE);
rl = ntfs_attr_find_vcn_nolock(ni, vcn, FALSE);
if (IS_ERR(rl)) {
err = PTR_ERR(rl);
if (!is_rollback)
......
......@@ -1297,7 +1297,7 @@ static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
read_lock_irqsave(&mftbmp_ni->size_lock, flags);
ll = mftbmp_ni->allocated_size;
read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
rl = ntfs_find_vcn_nolock(mftbmp_ni,
rl = ntfs_attr_find_vcn_nolock(mftbmp_ni,
(ll - 1) >> vol->cluster_size_bits, TRUE);
if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
up_write(&mftbmp_ni->runlist.lock);
......@@ -1727,8 +1727,8 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
read_lock_irqsave(&mft_ni->size_lock, flags);
ll = mft_ni->allocated_size;
read_unlock_irqrestore(&mft_ni->size_lock, flags);
rl = ntfs_find_vcn_nolock(mft_ni, (ll - 1) >> vol->cluster_size_bits,
TRUE);
rl = ntfs_attr_find_vcn_nolock(mft_ni,
(ll - 1) >> vol->cluster_size_bits, TRUE);
if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
up_write(&mft_ni->runlist.lock);
ntfs_error(vol->sb, "Failed to determine last allocated "
......
......@@ -933,17 +933,18 @@ err_out:
*
* It is up to the caller to serialize access to the runlist @rl.
*
* Since lcns must be >= 0, we use negative return values with special meaning:
* Since lcns must be >= 0, we use negative return codes with special meaning:
*
* Return value Meaning / Description
* Return code Meaning / Description
* ==================================================
* -1 = LCN_HOLE Hole / not allocated on disk.
* -2 = LCN_RL_NOT_MAPPED This is part of the runlist which has not been
* inserted into the runlist yet.
* -3 = LCN_ENOENT There is no such vcn in the attribute.
* LCN_HOLE Hole / not allocated on disk.
* LCN_RL_NOT_MAPPED This is part of the runlist which has not been
* inserted into the runlist yet.
* LCN_ENOENT There is no such vcn in the attribute.
*
* Locking: - The caller must have locked the runlist (for reading or writing).
* - This function does not touch the lock.
* - This function does not touch the lock, nor does it modify the
* runlist.
*/
LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn)
{
......
......@@ -66,6 +66,8 @@ typedef enum {
LCN_HOLE = -1, /* Keep this as highest value or die! */
LCN_RL_NOT_MAPPED = -2,
LCN_ENOENT = -3,
LCN_ENOMEM = -4,
LCN_EIO = -5,
} LCN_SPECIAL_VALUES;
extern runlist_element *ntfs_runlists_merge(runlist_element *drl,
......
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