[PATCH 3/25] NTFS: Use ntfs_malloc_nofs_nofail() in ntfs_runlists_merge()
in the two critical regions. This means we no longer need to
panic() when the allocation fails as it now cannot fail.
Signed-off-by: Anton Altaparmakov <[email protected]>
---
fs/ntfs/ChangeLog | 3 ++
fs/ntfs/runlist.c | 68 +++++++++++++++++++++++++++++++++++++++--------------
2 files changed, 53 insertions(+), 18 deletions(-)
9529d461d0992959026264b8fc002ac01d226708
diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -40,6 +40,9 @@ ToDo/Notes:
- Add fs/ntfs/malloc.h::ntfs_malloc_nofs_nofail() which is analogous to
ntfs_malloc_nofs() but it performs allocations with __GFP_NOFAIL and
hence cannot fail.
+ - Use ntfs_malloc_nofs_nofail() in the two critical regions in
+ fs/ntfs/runlist.c::ntfs_runlists_merge(). This means we no longer
+ need to panic() if the allocation fails as it now cannot fail.
2.1.23 - Implement extension of resident files and make writing safe as well as
many bug fixes, cleanups, and enhancements...
diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c
--- a/fs/ntfs/runlist.c
+++ b/fs/ntfs/runlist.c
@@ -35,7 +35,7 @@ static inline void ntfs_rl_mm(runlist_el
int size)
{
if (likely((dst != src) && (size > 0)))
- memmove(base + dst, base + src, size * sizeof (*base));
+ memmove(base + dst, base + src, size * sizeof(*base));
}
/**
@@ -95,6 +95,51 @@ static inline runlist_element *ntfs_rl_r
}
/**
+ * ntfs_rl_realloc_nofail - Reallocate memory for runlists
+ * @rl: original runlist
+ * @old_size: number of runlist elements in the original runlist @rl
+ * @new_size: number of runlist elements we need space for
+ *
+ * As the runlists grow, more memory will be required. To prevent the
+ * kernel having to allocate and reallocate large numbers of small bits of
+ * memory, this function returns an entire page of memory.
+ *
+ * This function guarantees that the allocation will succeed. It will sleep
+ * for as long as it takes to complete the allocation.
+ *
+ * It is up to the caller to serialize access to the runlist @rl.
+ *
+ * N.B. If the new allocation doesn't require a different number of pages in
+ * memory, the function will return the original pointer.
+ *
+ * On success, return a pointer to the newly allocated, or recycled, memory.
+ * On error, return -errno. The following error codes are defined:
+ * -ENOMEM - Not enough memory to allocate runlist array.
+ * -EINVAL - Invalid parameters were passed in.
+ */
+static inline runlist_element *ntfs_rl_realloc_nofail(runlist_element *rl,
+ int old_size, int new_size)
+{
+ runlist_element *new_rl;
+
+ old_size = PAGE_ALIGN(old_size * sizeof(*rl));
+ new_size = PAGE_ALIGN(new_size * sizeof(*rl));
+ if (old_size == new_size)
+ return rl;
+
+ new_rl = ntfs_malloc_nofs_nofail(new_size);
+ BUG_ON(!new_rl);
+
+ if (likely(rl != NULL)) {
+ if (unlikely(old_size > new_size))
+ old_size = new_size;
+ memcpy(new_rl, rl, old_size);
+ ntfs_free(rl);
+ }
+ return new_rl;
+}
+
+/**
* ntfs_are_rl_mergeable - test if two runlists can be joined together
* @dst: original runlist
* @src: new runlist to test for mergeability with @dst
@@ -621,11 +666,8 @@ runlist_element *ntfs_runlists_merge(run
if (drl[ds].lcn != LCN_RL_NOT_MAPPED) {
/* Add an unmapped runlist element. */
if (!slots) {
- /* FIXME/TODO: We need to have the
- * extra memory already! (AIA) */
- drl = ntfs_rl_realloc(drl, ds, ds + 2);
- if (!drl)
- goto critical_error;
+ drl = ntfs_rl_realloc_nofail(drl, ds,
+ ds + 2);
slots = 2;
}
ds++;
@@ -640,13 +682,8 @@ runlist_element *ntfs_runlists_merge(run
drl[ds].length = marker_vcn - drl[ds].vcn;
/* Finally add the ENOENT terminator. */
ds++;
- if (!slots) {
- /* FIXME/TODO: We need to have the extra
- * memory already! (AIA) */
- drl = ntfs_rl_realloc(drl, ds, ds + 1);
- if (!drl)
- goto critical_error;
- }
+ if (!slots)
+ drl = ntfs_rl_realloc_nofail(drl, ds, ds + 1);
drl[ds].vcn = marker_vcn;
drl[ds].lcn = LCN_ENOENT;
drl[ds].length = (s64)0;
@@ -659,11 +696,6 @@ finished:
ntfs_debug("Merged runlist:");
ntfs_debug_dump_runlist(drl);
return drl;
-
-critical_error:
- /* Critical error! We cannot afford to fail here. */
- ntfs_error(NULL, "Critical error! Not enough memory.");
- panic("NTFS: Cannot continue.");
}
/**
-
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