[PATCH 3/17] NTFS: - Change {__,}ntfs_cluster_free() to also take an optional attribute search context

Anton Altaparmakov
2005-10-31T14:26:37Z

NTFS: - Change {__,}ntfs_cluster_free() to also take an optional attribute
search context as argument. This allows calling it with the mft
record mapped. Update all callers.
- Fix potential deadlock in ntfs_mft_data_extend_allocation_nolock()
error handling by passing in the active search context when calling
ntfs_cluster_free().

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

---

fs/ntfs/ChangeLog | 11 +++++++----
fs/ntfs/lcnalloc.c | 41 +++++++++++++++++++++++++++++++++++------
fs/ntfs/lcnalloc.h | 40 +++++++++++++++++++++++++++++++++++-----
fs/ntfs/mft.c | 13 +++++++++----
4 files changed, 86 insertions(+), 19 deletions(-)

applies-to: 6a1fc55f654d6f7cb745bba032115d5590cc5931
511bea5ea2b2b330e67c9e58ffb5027caebf9052
diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
index 0a361dd..6e4f44e 100644
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -24,10 +24,13 @@ ToDo/Notes:

2.1.25-WIP

- - Change ntfs_map_runlist_nolock() and ntfs_attr_find_vcn_nolock() to
- also take an optional attribute search context as argument. This
- allows calling these functions with the mft record mapped. Update
- all callers.
+ - Change ntfs_map_runlist_nolock(), ntfs_attr_find_vcn_nolock() and
+ {__,}ntfs_cluster_free() to also take an optional attribute search
+ context as argument. This allows calling these functions with the
+ mft record mapped. Update all callers.
+ - Fix potential deadlock in ntfs_mft_data_extend_allocation_nolock()
+ error handling by passing in the active search context when calling
+ ntfs_cluster_free().

2.1.24 - Lots of bug fixes and support more clean journal states.

diff --git a/fs/ntfs/lcnalloc.c b/fs/ntfs/lcnalloc.c
index 8e60c47..75313f4 100644
--- a/fs/ntfs/lcnalloc.c
+++ b/fs/ntfs/lcnalloc.c
@@ -782,6 +782,7 @@ out:
* @ni: ntfs inode whose runlist describes the clusters to free
* @start_vcn: vcn in the runlist of @ni at which to start freeing clusters
* @count: number of clusters to free or -1 for all clusters
+ * @ctx: active attribute search context if present or NULL if not
* @is_rollback: true if this is a rollback operation
*
* Free @count clusters starting at the cluster @start_vcn in the runlist
@@ -791,15 +792,39 @@ out:
* deallocated. Thus, to completely free all clusters in a runlist, use
* @start_vcn = 0 and @count = -1.
*
+ * If @ctx is specified, it is an active search context of @ni and its base mft
+ * record. This is needed when __ntfs_cluster_free() encounters unmapped
+ * runlist fragments and allows their mapping. If you do not have the mft
+ * record mapped, you can specify @ctx as NULL and __ntfs_cluster_free() will
+ * perform the necessary mapping and unmapping.
+ *
+ * Note, __ntfs_cluster_free() saves the state of @ctx on entry and restores it
+ * before returning. Thus, @ctx will be left pointing to the same attribute on
+ * return as on entry. However, the actual pointers in @ctx may point to
+ * different memory locations on return, so you must remember to reset any
+ * cached pointers from the @ctx, i.e. after the call to __ntfs_cluster_free(),
+ * you will probably want to do:
+ * m = ctx->mrec;
+ * a = ctx->attr;
+ * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
+ * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
+ *
* @is_rollback should always be FALSE, it is for internal use to rollback
* errors. You probably want to use ntfs_cluster_free() instead.
*
- * Note, ntfs_cluster_free() does not modify the runlist at all, so the caller
- * has to deal with it later.
+ * Note, __ntfs_cluster_free() does not modify the runlist, so you have to
+ * remove from the runlist or mark sparse the freed runs later.
*
* Return the number of deallocated clusters (not counting sparse ones) on
* success and -errno on error.
*
+ * WARNING: If @ctx is supplied, regardless of whether success or failure is
+ * returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx
+ * is no longer valid, i.e. you need to either call
+ * ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
+ * In that case PTR_ERR(@ctx->mrec) will give you the error code for
+ * why the mapping of the old inode failed.
+ *
* Locking: - The runlist described by @ni must be locked for writing on entry
* and is locked on return. Note the runlist may be modified when
* needed runlist fragments need to be mapped.
@@ -807,9 +832,13 @@ out:
* on return.
* - This function takes the volume lcn bitmap lock for writing and
* modifies the bitmap contents.
+ * - If @ctx is NULL, the base mft record of @ni must not be mapped on
+ * entry and it will be left unmapped on return.
+ * - If @ctx is not NULL, the base mft record must be mapped on entry
+ * and it will be left mapped on return.
*/
s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count,
- const BOOL is_rollback)
+ ntfs_attr_search_ctx *ctx, const BOOL is_rollback)
{
s64 delta, to_free, total_freed, real_freed;
ntfs_volume *vol;
@@ -839,7 +868,7 @@ s64 __ntfs_cluster_free(ntfs_inode *ni,

total_freed = real_freed = 0;

- rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, NULL);
+ rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, ctx);
if (IS_ERR(rl)) {
if (!is_rollback)
ntfs_error(vol->sb, "Failed to find first runlist "
@@ -893,7 +922,7 @@ s64 __ntfs_cluster_free(ntfs_inode *ni,

/* Attempt to map runlist. */
vcn = rl->vcn;
- rl = ntfs_attr_find_vcn_nolock(ni, vcn, NULL);
+ rl = ntfs_attr_find_vcn_nolock(ni, vcn, ctx);
if (IS_ERR(rl)) {
err = PTR_ERR(rl);
if (!is_rollback)
@@ -961,7 +990,7 @@ err_out:
* If rollback fails, set the volume errors flag, emit an error
* message, and return the error code.
*/
- delta = __ntfs_cluster_free(ni, start_vcn, total_freed, TRUE);
+ delta = __ntfs_cluster_free(ni, start_vcn, total_freed, ctx, TRUE);
if (delta < 0) {
ntfs_error(vol->sb, "Failed to rollback (error %i). Leaving "
"inconsistent metadata! Unmount and run "
diff --git a/fs/ntfs/lcnalloc.h b/fs/ntfs/lcnalloc.h
index a6a8827..aa05185 100644
--- a/fs/ntfs/lcnalloc.h
+++ b/fs/ntfs/lcnalloc.h
@@ -27,6 +27,7 @@

#include <linux/fs.h>

+#include "attrib.h"
#include "types.h"
#include "inode.h"
#include "runlist.h"
@@ -44,13 +45,14 @@ extern runlist_element *ntfs_cluster_all
const NTFS_CLUSTER_ALLOCATION_ZONES zone);

extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
- s64 count, const BOOL is_rollback);
+ s64 count, ntfs_attr_search_ctx *ctx, const BOOL is_rollback);

/**
* ntfs_cluster_free - free clusters on an ntfs volume
* @ni: ntfs inode whose runlist describes the clusters to free
* @start_vcn: vcn in the runlist of @ni at which to start freeing clusters
* @count: number of clusters to free or -1 for all clusters
+ * @ctx: active attribute search context if present or NULL if not
*
* Free @count clusters starting at the cluster @start_vcn in the runlist
* described by the ntfs inode @ni.
@@ -59,12 +61,36 @@ extern s64 __ntfs_cluster_free(ntfs_inod
* deallocated. Thus, to completely free all clusters in a runlist, use
* @start_vcn = 0 and @count = -1.
*
- * Note, ntfs_cluster_free() does not modify the runlist at all, so the caller
- * has to deal with it later.
+ * If @ctx is specified, it is an active search context of @ni and its base mft
+ * record. This is needed when ntfs_cluster_free() encounters unmapped runlist
+ * fragments and allows their mapping. If you do not have the mft record
+ * mapped, you can specify @ctx as NULL and ntfs_cluster_free() will perform
+ * the necessary mapping and unmapping.
+ *
+ * Note, ntfs_cluster_free() saves the state of @ctx on entry and restores it
+ * before returning. Thus, @ctx will be left pointing to the same attribute on
+ * return as on entry. However, the actual pointers in @ctx may point to
+ * different memory locations on return, so you must remember to reset any
+ * cached pointers from the @ctx, i.e. after the call to ntfs_cluster_free(),
+ * you will probably want to do:
+ * m = ctx->mrec;
+ * a = ctx->attr;
+ * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
+ * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
+ *
+ * Note, ntfs_cluster_free() does not modify the runlist, so you have to remove
+ * from the runlist or mark sparse the freed runs later.
*
* Return the number of deallocated clusters (not counting sparse ones) on
* success and -errno on error.
*
+ * WARNING: If @ctx is supplied, regardless of whether success or failure is
+ * returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx
+ * is no longer valid, i.e. you need to either call
+ * ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
+ * In that case PTR_ERR(@ctx->mrec) will give you the error code for
+ * why the mapping of the old inode failed.
+ *
* Locking: - The runlist described by @ni must be locked for writing on entry
* and is locked on return. Note the runlist may be modified when
* needed runlist fragments need to be mapped.
@@ -72,11 +98,15 @@ extern s64 __ntfs_cluster_free(ntfs_inod
* on return.
* - This function takes the volume lcn bitmap lock for writing and
* modifies the bitmap contents.
+ * - If @ctx is NULL, the base mft record of @ni must not be mapped on
+ * entry and it will be left unmapped on return.
+ * - If @ctx is not NULL, the base mft record must be mapped on entry
+ * and it will be left mapped on return.
*/
static inline s64 ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
- s64 count)
+ s64 count, ntfs_attr_search_ctx *ctx)
{
- return __ntfs_cluster_free(ni, start_vcn, count, FALSE);
+ return __ntfs_cluster_free(ni, start_vcn, count, ctx, FALSE);
}

extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
diff --git a/fs/ntfs/mft.c b/fs/ntfs/mft.c
index 15df34f..5577fc6 100644
--- a/fs/ntfs/mft.c
+++ b/fs/ntfs/mft.c
@@ -1952,20 +1952,21 @@ restore_undo_alloc:
NVolSetErrors(vol);
return ret;
}
- a = ctx->attr;
- a->data.non_resident.highest_vcn = cpu_to_sle64(old_last_vcn - 1);
+ ctx->attr->data.non_resident.highest_vcn =
+ cpu_to_sle64(old_last_vcn - 1);
undo_alloc:
- if (ntfs_cluster_free(mft_ni, old_last_vcn, -1) < 0) {
+ if (ntfs_cluster_free(mft_ni, old_last_vcn, -1, ctx) < 0) {
ntfs_error(vol->sb, "Failed to free clusters from mft data "
"attribute.%s", es);
NVolSetErrors(vol);
}
+ a = ctx->attr;
if (ntfs_rl_truncate_nolock(vol, &mft_ni->runlist, old_last_vcn)) {
ntfs_error(vol->sb, "Failed to truncate mft data attribute "
"runlist.%s", es);
NVolSetErrors(vol);
}
- if (mp_rebuilt) {
+ if (mp_rebuilt && !IS_ERR(ctx->mrec)) {
if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
a->data.non_resident.mapping_pairs_offset),
old_alen - le16_to_cpu(
@@ -1982,6 +1983,10 @@ undo_alloc:
}
flush_dcache_mft_record_page(ctx->ntfs_ino);
mark_mft_record_dirty(ctx->ntfs_ino);
+ } else if (IS_ERR(ctx->mrec)) {
+ ntfs_error(vol->sb, "Failed to restore attribute search "
+ "context.%s", es);
+ NVolSetErrors(vol);
}
if (ctx)
ntfs_attr_put_search_ctx(ctx);
---
0.99.9